Typhoons of Pohnpei and Kosrae

Prior to the typhoon of 1905 both Pohnpei and Kosrae had experienced typhoons.

An extended excerpt from Typhoons in Micronesia: A History of Tropical Cyclones and their Effects until 1914. Dirk H.R. Spennemann, Division of Historic Preservation Saipan, CNMI, 2004. ©Dirk H. R. Spennemann, 2004. Available as: CNMITyphoon.pdf from https://www.researchgate.net/publication/277964781_Typhoons_in_Micronesia_A_history_of_tropical_cyclones_and_their_effects_until_1914

The Protestant Luther Gulick (1859), based on local informants and own his climatological observations mentioned that on Pohnpei

“typhoons of the China Sea, and even of the seas North of the Ladrones, about the Bonin Islands, almost never extend to this island.”

But Gulick also mentioned that

“once, during the youth of the very oldest inhabitants now living [in 1858], a devastating wind swept over the island, so tearing up the bread- fruit trees—the principal reliance for food—that an awful famine ensued, and large numbers died. It would seem that this was a cyclone” (Gulick 1859).

Genealogical reckoning would date this event to the late eighteenth century. It is tempting to correlate this event with the ~1770 typhoon mentioned for Mokil, especially in the light of later events, where Pohnpei, Mokil and Pingelap are equally affected, but this might be stretching the data too far. On the other hand, Gulick likewise mentions that the oldest inhabitants of Kosrae could also remember a devastating typhoon which resulted in widespread famine and death of many Kosraeans. Given the overall scarcity of very destructive typhoon events in that part of Micronesia, Gulick (1859) assumed that this may have been the same event as that on Pohnpei.

According to the German physician Dr. Max Girschner (1907), oral histories comment on an extremely severe typhoon, accompanied by storm surges, that devastated Pohnpei in the mid 1820s. It is possible that this was the event that Gulick commented on but that Gischner’s reckoning is incorrect, or it may be the 1868 event (see below). The discrepancy in dates demonstrates the problems inherent in accurately dating events mentioned in oral traditions.

While typhoons are rare in Pohnpei, Gulick was to be exposed to an exception to the rule in 1868. A typhoon struck Pohnpei, devastating the Protestant mission settlement, then in Kiti. The church was destroyed and the mission house damaged. All buildings in the local village of Kiti were blown away and the food crops substantially damaged (Crawford & Crawford 1967, p. 167). Given that little damage is reported for the other areas on Pohnpei is indicative of both the community-centricity of the Protestant missionaries, but also suggests that the typhoon passed to the south of the island. In the absence of more detailed information we can only speculate that Kiti was not near the eye-wall cloud and that the typhoon passed some distance to the south. 

On 15 March 1874 a typhoon struck Kosrae. On this occasion, Bully Hayes’ vessel Leonora as well as two whalers, trapped in Utwe Harbor on the south coast of the island without much room to move or attempt to escape, were sunk (Lubbock 1931).

Kosrae 1891

The 3-4 March 1891 typhoon, which was very destructive on Ngatik and Kosrae was also felt on Jaluit, but only to a much lesser extent, presumably as a tropical storm (cf. Deutsche Kolonialzeitung 16[27], 1900, 300-301). Gaining momentum as it traveled west, the typhoon became severe over Kosrae, but seems to have only been felt as a storm on Pohnpei. In the absence of wind directions we cannot reconstruct whether the typhoon passed Kosrae to the north or, as is more likely based on the damage described, to the south. The 1891 typhoon on Kosrae damaged or destroyed most of the island and its buildings (Crawford & Crawford 1967, p. 256) and threw up a two meter high and three to four kilometers long hurricane bank on the reef platform (Krämer 1927, p. 23). 

The mission histories report that “scarcely half a dozen houses were left standing on Kusaie [Kosrae], and the breadfruit and cocoanut trees are almost wholly destroyed. The Gilbert Islands settlement suffered the most; all but two or three of their native houses were destroyed” (Bliss 1906, p. 140). The damage level observed is indicative of a typhoon of greater than 100 knots wind speed. The missionaries’ house was unroofed and its contents soaked. Corrugated iron sheeting from the girls’ school roof was blown for several hundred meters (Bliss 1906, p. 140). The devastation of the food supply resulted in severe food shortages.

There is evidence for another typhoon or a westerly burst at the onset of an El Niño cycle in the eastern Carolines in late November 1898. During that month Pingelap was affected by a presumed storm wave set-up washing over the island (Hambruch 1932). On 28 November 1898, Ngatik was also awash, whether by a storm surge or by a substantially higher than normal sea level can not be determined. Given that the water did not recede for eight days, a westerly burst is more likely than a typhoon. Many people could only survive by climbing into the tops of coconut palms (Hahl 1980, p. 77). During that event all breadfruit trees died, half the coconuts were uprooted and the island of Ngatik lost ap- proximately 10 acres at its southwestern corner. All livestock was lost (Berg 1900). The event also flooded the small islet of Peina at the northern reef platform of Ngatik (Eilers 1934, p. 334).

The 1905 Typhoon

[There is circumstantial evidence to link the 1905 typhoon event to the El Niño event. The German Imperial Government’s physician Schwabe mentions in his quarterly report that the wind patterns in early 1905 were different than usual: the NE trade winds blew until June. He speculates that the typhoon incident which occurred on the last day of the report period may be related to this shift in wind patterns (Schwabe 1905b).]

From: Stormy years: the ENSO phenomenon and typhoons in the Marshall Islands. Spennemann, & Marschner, Albury 1994

[Typhoons in Micronesia excerpt continued]

On 19 and 20 April 1905 a very severe typhoon struck the islands of the Eastern Carolines. Spawned somewhere in or to the south(east) of the Marshall Islands, where it would have been merely a tropical storm, the typhoon quickly gathered strength and speed. It struck a number of islands and atolls from Kosrae to Pohnpei, with the low atolls, such as Pingelap and Mokil, Ant, Pakin, the most severely hit. The typhoon then continued on and struck the atolls of Oroluk, Fananu, Nomwin, Inissifau-Pissila, Piherar and Olol (see p. 52) (Berg 1906c). The incipient island on Minto Reef was completely destroyed.

The total casualty and damage figures vary. The German Vice-Governor and district administrator for the Eastern Carolines, Victor Berg states in his annual report that in total 46 people died, six Europeans and about 200 Micronesians were injured (Berg 1906c). Wolfgang Treue in his thesis on the role of the Jaluit Gesellschaft mentions that the total damages in the Carolines were 4 million Imperial German Marks, with 1.5 million of damages among white traders and settlers. According to Treue (1940, p. 143), 25 people were killed, 5 Europeans and over 300 locals injured.

Based on the available data the path of the typhoon can be reconstructed as running from Kosrae to Gaferut. As it apparently was not felt at Faraulep, Fais or Ulithi, nor in the Marianas, it must have then veered off north or petered out (figure 5.2). ... The fact that Kosrae was struck by wave set-up well before the arrival of the typhoon indicates that the system had a slow forwards speed, but was quite intense.

Kosrae

Kosrae was the first island to be struck by the full fury of the typhoon. The event was preceded on 18 April by a storm-induced wave set-up, which carried away several huts on the beach (Garland, G. 1905d). The wind effects of the typhoon struck Kosrae on 19 April, lasting about six hours, with the eye of the storm passing over the island at approximately 09:00 (Channon 1905).

According to the Swedish trader John V. Melander, an eye-witness, the storm started on 19 April at 04:00 with winds from the west, accompanied by a high surge; at 06:30 the winds came from northwest, changing to north and then northeast with a barometric pressure of 620mmHg. The winds changed to northeast by 08:00, when they reached their greatest intensity, but faded away by 10:00. By 11:00 it was all over (Puttfarcken 1905a). ... Based on the wind directions, the typhoon seems to have passed over the southern part of the island, or just to the south of it. Based on the damage observed (see below), we can assume that the typhoon would have been a category 3 event with wind speeds of 105 to 115 knots.

In addition, during the event a small “earthquake” was felt at Lelu. Two short and sharp shocks were followed by a weak and long rumble lasting about 5-10 minutes (Berg 1905b).

On the island of Kosrae, two women and three children were killed and another 25-30 injured (Garland 1906d). The chief of Kosrae was struck by a flying piece of wood in his leg (Melander 1905). Of the mission staff, the teacher, Ms Wilson, suffered a broken rib after being hit by a flying piece of wood, while one of the Marshallese pupils was struck on the head cracking her skull. The lack of proper medical facilities meant that although she survived the incident, she died of complications several weeks later (Rife 1905c). The German government physician, Girschner (1907a), reports in his annual medical report for the Eastern Carolines for the financial year 1905/06 that on Kosrae five persons died as a direct result of the storm.

Sarah Garland, watching the typhoon from the Morning Star, mentions that as a result of the torrential rainfall the creeks had turned into torrents and that the harbor of Kosrae near the mission station was colored brown by the muddy waters flowing down from the hills, carrying with them debris of all sorts. In addition, thousands of dead fish were observed floating about, killed by the surf pounding the reef and presumably also the high silt load in the water. After the event, the air was reported to have been filled with a nearly unbearable stench of decaying vegetation (Garland, S. 1905b). As on Pohnpei (see p. 88), the environmental damage to the old growth forest on the hills was substantial, with a large proportion of the trees on Kosrae blown down. As Rife put it: “the beauty of the island is gone and it will require years for it to reach its former splendor” (Rife 1905c).

All coconuts were blown off the palms; young palms were uprooted, and old ones snapped (Melander 1905). All trees were stripped of their leaves and many coconuts lost their tops. All breadfruit trees were either uprooted or lost all but their main branches (Channon 1905). George Garland reported to Vice-Governor Berg that on Kosrae all breadfruit were down, and that all but one house was blown down as well (Berg 1905d).

Rife describes the food trees as “perfectly bare and... not even leaves left to make a show of green” (Rife 1905c). This damage level is consistent with wind speeds around 110 to 120 knots, which would suggest a typhoon pressure of about 720 mmHg. Fortunately, the Kosraeans were not entirely dependent on coconut, breadfruit and bananas and could make up some of these losses by increasing their reliance on root crops (Rife 1905c). During his inspection in July 1905, Berg concludes that the people still had enough food (Berg 1905b).

The trader Melander’s property was destroyed, the houses blown down, the wharf and the rain gauge (which he operated for the government) were washed away, and his land reclamation at the waterfront eroded by the waves (Melander 1905). At Lelu 30% of all coconut palms were down, most houses, the new mission church, and (almost?) all plantations destroyed. All other churches had lost their roofs, and some had suffered structural damage to the walls as well (Rife 1905c).

No data on the economic impact and damage bill have been published or included in the archival files. The described damage to the plantations and infrastructure can be estimated to amount to at least RMk 1,000,000 (US$ 250,000) if we use the Pohnpei estimates (p. 90) as a basis for comparison, though, given that Pohnpei was more ‘developed’ the real damage bill for Kosrae was probably less than the extrapolated figure.

...

Pingelap

The typhoon did affect Pingelap on 19 April from 20:00 to 23:00, blowing over all houses and even destroying the stone church. Garland estimates approximately 50% damage to coconut palms (Garland 1906d). Accord- ing to the German government statistics four people perished (Girschner 1907a). Seven years earlier, in 1898, Pingelap had already been affected by storm surge washing over the atoll (Hambruch 1932).

Wilson, en route from Kosrae to Pohnpei less than a week after the typhoon, mentions that the island looked very desolate and that many had been injured by the flying debris. Later observations mention that the typhoon had destroyed a large part of the coconut palms, killed four Pingelapese and injured many more (Puttfarcken 1905a). We are uninformed as to whether the entire atoll was awash with the storm surge or whether most of the damage was purely windborne. Sarah Garland mentions that some canoes came out to meet the mission ship, which would indicate that not the entire atoll had been awash as they would have floated away (Garland, S. 1905).

The casualty figures for Pingelap are troubling. The German government physician, Girschner, reports in his annual medical report for the Eastern Caro- lines for the financial year 1905/06 that on Pingelap four persons died as a direct result of the storm, but that 113 Pingelapese died as a result of starvation or illnesses following the typhoon (Girschner 1907a).

Mwoakilloa

The typhoon raged on Mwaokilloa on 20 April, from 00:00 to about 04:00. All houses were blown or washed over and almost all canoes were destroyed (Garland, G. 1905d). Sarah Garland described the typhoon impact on Mokil as more violent than on Pingelap (Garland, S 1905). This would suggest that the typhoon picked up intensity as it moved west—a common phenomenon—or that it passed the atoll to the south while it passed Pingelap to the north. The German government physician, Max Girschner, reports that on Mokil one person died as a direct result of the storm (Girschner 1907a), drown- ing in the surge. The SMS Condor, coming from Samoa, via Jaluit stopped in December 1905 at Mokil, but reported no post-typhoon problems (Condor 1906). Mokil seemed to have overcome typhoon effects by November 1907 (Grösser 1907).

Pohnpei

On Pohnpei the storm began at 09:00 on April 20, 1905 and lasted for approximately 6 hours (Gray 1905). Captain Puttfarcken of SMS Seeadler reported that on Pohnpei the storm started on midday 20 April coming from a northerly direction, with 713.5 mmHg (951 hPa) as lowest barometer level. After five hours it was all over (Puttfarcken 1905b). Berg, at the time at Keralap in the southwest of Pohnpei, noted the eye passage. The wind damages to vegetation described below suggest a wind speed of 110-120 knots.

The hills of Pohnpei are described as bare (Berg 1905a; Duffner 1910), due to the wind stripping the leaves off the trees and the tree trunks smashing vegetation as they fell. The exposed root systems, coupled with the heavy rains started some erosion. Berg argues that based on the damage this typhoon exacted on the hillside vegetation cover, a typhoon like this had not occurred for ‘over a thousand years’ (Berg 1906c). It appears that the typhoon of 1898 that affected Mokil and Pingelap, passed too far south of Pohnpei to have any effect.

On Pohnpei, fifteen Pohnpeians were killed, three or four Europeans and some 300 Pohnpeians injured. All houses were destroyed including the contents and personal belongings (Berg 1905e; 1906c). Berg mentions that he was surprised that the number of dead and injured was not greater because the wind carried items, such as corrugated roofing iron, parts of houses and trees, furniture, stones from masonry and the like (Berg 1905a). Berg mentions in his official dispatch that the strength of the typhoon can be best visualized by his experience of seeing a coconut palm with a trunk diameter of half a meter cut by a flying piece of corrugated iron (Berg 1905e; Duffner 1910). Indeed, one of the Pohnpeians had his head half severed off because of such a circumstance (Berg 1905a).

The total damage was estimated to be about 4 Million Imperial Marks, then about US$ 1 million (about US$ 20.7 million in 2004 terms). Only half a million RMk of that damage bill was from property of Europeans. The latter is distributed as losses of RMk 150,000 to the Imperial German Government, RMk 350,000 to the traders and missions and another RMk 10,000 to other Europeans (Berg 1905a; 1905e).

Upon his arrival as part of a relief mission, Captain Puttfarcken reported that the typhoon damage at Kolonia was visible from sea, with most of the coconut palms evidently damaged, many of which had fallen over while many others had lost their tops. A ground inspection showed that about 50% of all coconut palms were damaged, and many breadfruit trees had been toppled (Puttfarcken 1905b).

While on most of Pohnpei the damage of the typhoon was limited to wind impact, at the harbor of Kolonia the sea rose above the level of the seawalls and quay, causing a canoe moored at the quay to be thrown over a nearby house (Berg 1905a). The weather side was most affected. The small islands of Na, Naningi, and Mall were water washed and the island of Nahpali, at the entrance of Madolenihmw Harbor was breached in two locations by the storm surge (Berg 1905a). The small island of Namaur, a sandy islet at the eastern entrance of Madolenihmw Harbor, was completely washed away (Hambruch 1932).

All houses in Kolonia comprising the government buildings, including the brand new residence of the German Governor, the church, the establishment of the Capuchin mission and two trading houses were reported as destroyed. Most of them were blown off the stone pillars on which they had been erected to protect them against humidity. Often, only the pillars alone remained (Puttfarcken 1905a; Duffner 1910). “The flattest wreck is the Governor’s new house”, as Sarah Garland expressed her first impressions of the damage (Garland, S. 1905a). The remnants of the Spanish fortification wall of Kolonia survived the onslaught of the winds, but were damaged nonetheless and lost a number of stones (Berg 1905a). Almost all Pohnpeian-owned houses, including the property contained therein, was destroyed.

The torrential rainfalls were so strong that they set off landslides, possibly facilitated by European land clearing activities. One such massive landslide destroyed a European house near Kolonia (Anon. 1905b).

Local food supplies are reported as extensively damaged, with all coconuts stripped of fronds and some even with the tops snapped off. According to Berg tens of thousands of coconut palms were destroyed (Berg 1906c). Less than a quarter of the palms could be classified as having only minor damage. It was estimated that even limited copra production could not be resumed for at least a couple of years (Missionary Herald August 1905). Before the typhoon, attempts had been made to establish copra as a cash crop economy on Pohnpei, even though the high rainfall and humidity made drying almost impossible. By 1905 seven coconut plantations, totaling 8,400 aces had been cleared and planted (McKinney 1947, p. 67; Hanlon 1981, p. 66). Essentially, the April 1905 typhoon put an end to the German hopes of turning Pohnpei into a copra producing island.

Many breadfruit trees were uprooted and blown over, while the remaining were not only defoliated but also extensively damaged and would take a few years to recover (Berg 1906c). This damage had a double impact: because yams were traditionally planted intercropped with breadfruit, in a fashion that the yam vines climbed up the tree trunks, the toppling of the breadfruit trees also affected much of the yams harvest (Hambruch 1932, p. 347). In addition, all banana plants were destroyed. Many domestic animals, mainly pigs were killed in the event, both from drowning (on the low lying islands) and from falling debris (on the main island) (Berg 1905a).

The typhoon also caused substantial damage to local and regional shipping. The steam launch Fliege of the German administration, which had taken Berg on his Easter holiday camping trip, sank near Keparalap Island, with three of the six crew as casualties, the Portuguese captain and two Pohnpeian deck hands (Puttfarcken 1905a). In addition, almost all Pohnpeian canoes were destroyed, thrown ashore and damaged on rocks or trees, thus severely curtailing the Pohnpeians mobility and the administration’s ability to assist in disaster relief. To compound matters, this restricted the ability of the Pohnpeians to obtain fish for food (Girschner 1907). The brand new government schooner Ponape, as well as the motor schooner Diana, owned by the Jaluit Gesellschaft, were blown onto the reefs. While the Ponape could be successfully refloated, the Diana had to be auctioned off for scrap (Duffner 1910).

Later storms

There is a commonly accepted argument that the typhoon risk in Pohnpei is minimal and that the 1905 typhoon described in this study was the last time a severe typhoon struck the island. Yet a typhoon grazed the island on 11 December 1925 (OPNAV 1944b, p. 7). Since then typhoons Lola (31 May 1972) and (also) Lola (18 May 1986) have affected Pohnpei directly, both Beaufort 11 storms impacting on the island (Ashby 1990, p. 104), as well as typhoons Russ (1990) and Axel (1992).

[End material from Typhoons in Micronesia]

Lola 1957

Typhoon Lola Pays A Call

A most unladylike intruder by the name of Lola paid a call upon the Trust Territory in mid-November 1957.

Lola was a typhoon of major proportions. Sweeping along like a bulldozing broom, she smashed down valuable breadfruit and coconut trees, submerged crops, wrecked homes and generally produced havoc as she rolled on from the Marshalls through Ponape, Truk, Guam, and up to Rota.

The typhoon which caused more over-all damage than any previously recorded within the territory, brought no loss of life and no major bodily injuries as far as is known, although many times tragedy knocked hard and close. In the face of danger, numerous. spontaneous acts of valor came to the fore.

...

Lola entered Ponape District on November 12, leaving havoc, destruction and debris as she whirled on her way. Not for fifty years had Ponape had a typhoon. It was generally considered to be out of the typhoon  path.  But reports from atolls and islands throughout the area repeated the story of coconut and breadfruit trees destroyed, and of food shortage imminent after the windfall of nuts on the ground would have been made into copra or consumed for food, and the breadfruit eaten.

Kolonia, the Ponape District center, was in the direct path of the storm, as were the islands immediately around it. Knowing that the typhoon was coming, the people of Kolonia took shelter in the hospital building and warehouse, District Administration office, Intermediate School, agriculture station, and in churches and other buildings of the religious missions. For some 250 or more storm refugees in these shelters, C-rations (individual canned foods), rice and sugar were issued by the Administration, also small quantities of kerosene to provide fuel for the ranges on which people prepared hot food and beverages.

The damage to buildings and utilities at Kolonia was considerable. Destroyed were the temporary warehouses and carpenter shed on the site of the new Pacific Islands Central School, and ruined was all of the bagged cement therein, a total loss representing some five thousand dollars.

Ponape's power and telephone systems were heavily hit by falling trees; roads were eroded, and bridges and culverts damaged, with a loss of approximately thirty-three thousand dollars in government property alone.

In addition to buildings damaged and public works systems affected, four vessels went aground in the bay - all privately owned. These were the LUCKY, the CULVER, the MARU, and the ASCOY. All except the first were expected to be refloated. The LUCKY, which was directly hit and forced high onto the reef, was not thought to be salvable.

Cacao pod production in Ponape was reduced by at least fifty per cent by the typhoon, according to estimates, and copra production here also is diminishing as a result of the high winds which blew immature nuts to the ground, or weakened them so that they began falling off before ripening.

At Kahlap in Mokil Atoll, also in Ponape District, the sea rose inland, carrying logs and debris onto the main settlement, destroying most of the dwellings and all of the canoe houses and - still more serious - many canoes and whale boats. The main taro patch was filled with water to a height of five feet, causing the residents to dive for taro as they needed it following the storm.

The outlook here, as in other areas affected, pointed to taro as a temporary replacement for the breadfruit, coconuts and pandanus destroyed. These will take months or years to re-grow. The taro in the patches affected by salt water was usable and sufficient in many cases to provide food for about three months, but after that time, food from outside sources would be necessary, as new taro plantings could not be made for approximately five months, which is the time required to leach the salt out of the soil.

Similarly at Pingelap Atoll in Ponape District, damage was extensive, and relief in the form of food imported from the outside was necessary to sustain the inhabitants. Since typhoons in Ponape District have been so rare, the blow was more stunning than in the Marshalls, for instance, where storms are more common.

Lola 1972

Lola in May 1972 was attributed to the early start of an El Niño event that year. Above is damage to a house after Typhoon Lola, 1972. Images from Trust Territory Photo Archives.

Women near rubble left by Typhoon Lola, 1972. 

Lola June 1986

Pohnpei a major Disaster Area due to Lola
National Union, June 1986

Kolonia, Pohnpei- US President Ronald Reagan on June 3 declared Pohnpei Island, the capital of the Federated States of Micronesia, some 907 miles southeast of Guam, a major disaster area due to the damages left by Typhoon Lola, according to Pohnpei State Governor's Office release.

Typhoon Lola hit Pohnpei May17 and raged through the following day, snapped electrical poles, downed power lines, uprooted trees and crops and leveled hones with strong winds and high seas that damaged crops on the outer islands and airstrips on Mokil and Pingelap several hundred miles east of Pohnpei island before making its way toward the north west of the Pacific.

Reagan's declaration makes Pohnpei Island eligible for U.S. disaster assistance, something both Pohnpei Governor Resio Moses and ESM President Tosiwo Nakayama had earlier requested due to severity of the impact of Typhoon Lola which hit Pohnpei on May 17, the release said. 

Assistance comes under three major categories of individual housing assistance, public assistance and small business loans, Federal Emergency Management Agency (FEMA) Chief Tommie C. Hamer, who was appointed Coordinating Officer to assist recovery efforts, said.

Typhoon damage Kapingamarangi village, Ponape. Trust Territory Photo Archive

Residents of Pohnpei Island whose losses include homes, cook houses, shower and outhouses including repair of damaged Pohnpei government facilities and the removal of debris from roads and urban areas will be eligible for direct grant compensation, the release said, adding that agriculture losses such as damaged root crops, downed banana, breadfruit or coconut trees or dead livestock are not eligible under these programs for disaster assistance.

Businesses and individuals who lost personal property such as cars, furniture, clothing, video equipment,etc., are eligible to apply for Small Business Administration loans.

In his June 5 letter to President Nakayama thanking him for FSM government's assistance during the typhoon, Gov. Moses noted that while FEMA assistance will be available, it will not be extendable to agricultural (crop) damages, adding that "most of our citizens are subsistence 'croppers' and a lot of them will need assistance."

Pohnpei was hit by another typhoon Lola in 1957 and Typhoon Ophelia in 1958 which also caused damage to crops and homes.

Landslides due to rainfall from formation stages of Isa and Jimmy 1997

The combined effects of Super Typhoon Isa and Tropical Storm Jimmy, approximately 1 week apart, triggered over 30 landslides on the island of Pohnpei during the night of April 20-21,1997. Most of these landslides occurred in the Sokehs District, located along the northwest coast and resulted in the destruction of 14 dwellings in Sokehs Municipality and 19 fatalities in the villages of Oumoar and lohl. Precipitation from Super Typhoon Isa on April 11-13 saturated slopes on the island. One week later, over 25 cm (10 in) of rain from Tropical Storm Jimmy fell during a 4-hour period, triggering landslides that resulted in destruction of homes and loss of life. In this report, we describe the landslides and the geologic materials that failed during the April 1997 storms, present an inventory map of the landslides, discuss the landslide hazards that remain, and make recommendations for future landslide hazard mitigation and studies for assessment of future landslide hazards.

PHYSICAL AND GEOLOGIC SETTING

The island of Pohnpei lies approximately 800 km north of the equator (-7° N., 158° E.) and experiences a tropical climate. Average precipitation ranges from about 400 cm/yr (160 in/yr) at the coast to almost 900 cm/yr (355 in/yr) in the interior mountains. The island is roughly circular in shape and characterized by steep mountains covered with dense vegetation. Geologically, Pohnpei is a remnant of a large shield volcano built up from the surrounding sea floor by episodic eruptions of slightly alkalic basaltic lavas dating back 9 million years (Spengler and others, 1991). The island lacks extensive coastal alluvial plains around its perimeter because of regional sub- sidence and sea-level rise (Spengler and others, 1991). The coast lacks beaches and is characterized by basaltic outcrops with adjacent mangrove swamps. A barrier reef surrounds most of the island.

STORMS TRIGGERING THE LANDSLIDES

Rainfall from Super Typhoon Isa (April 11-13 ) totaled more than 12.7 cm (5 in) of rainfall at the National Weather Service station at Kolonia (fig. 2). One week later, after light to moderate rain throughout most of the day on April 20, more than 25 cm (10 in) fell during a 4-hour period between

10:00 p.m. on the 20th and 2:00 a.m. on the 21st at the Kolonia station. The Kolonia station was the only recording rain gauge on the island at the time of these storms. The gauge is located approximately 5 km northeast of the center of the area of major landslide concentration and may not have recorded rainfall levels that were as great as those that occurred near Oumoar and lohl (fig. 2).

Reports of stream levels observed during the storm indicated that maximum precipitation occurred near the area of concentrated landsliding in Sokehs Municipality and that the rainfall decreased with a steep gradient away from this area. Although quantitative data are lacking, it appears that an intense precipitation cell was centered over the area of maximum landslide concentration for several hours. Residents of Oumoar and nearby areas within Sokehs Municipality reported that the landslides that caused the fatalities and property destruction occurred after about 10:30 p.m., April 20.

[Report continues to cover landslide geology.]

Source: Landslides Triggered by the April 1997, Tropical Storms in Pohnpei, Federated States of Micronesia. Edwin L Harp, William Z. Savage. U. S. Geological Survey Open-File Report 97-696 Denver, Colorado 80225, 1997.

Follow-up report on recovery efforts from FSM Information Services

Landslide Update: Two More Bodies Recovered Wednesday Afternoon, April 23 and Two More on Thursday, April 24

PALIKIR, Pohnpei (FSM Information Service): April 25, 1997 - Four more bodies of minors were recovered at the landslide sites, on Wednesday afternoon, April 23, 1997, one identified as Densa Kirielmwo, age unknown was discovered at the Iohl site and Erleen Peren, age 2, was discovered at the Oumor site; on April 24, bodies of Luisa Peren, 36, and of her son, Mikel Peren, 8 years old were both recovered at the Oumor site but no recovery was made at the Iohl site.

It has been, reportedly confirmed, that Benancio Kirielmwo who was listed among the missing persons was in Hawaii during the disaster. But a girl was recovered Wednesday, April 23, 1997, at Iohl site was identified as Denesa Kirielmwo, whose name was not in the original list.

One of the survivors, identified as Ester Kirielmwo was referred to the Philippines for medical treatment the night of April 23, 1997, accompanied by Dr. Johnny Hedson, was taken to Guam Memorial Hospital upon arrival at Guam as her condition deteriorated. She will remain there until she is well to return home. Ester is the wife of Francisco Kirielmwo still listed missing at the Iohl site.

With the good weather, rescue operations at both sites continued Friday, April 25, but no new discovery have been reported.

[Note that during 1997 a moderate to strong El Niño would develop, although this would not be declared by the weather services until later in the year. Lola 1972 and Isa/Jimmy were both storms that came ahead of the typical fall El Niño time frame. Again in 2023 on April 20 a tropical depression would bring damage to Pohnpei ahead of an incipient El Niño event.]       

Tropical storm Faxai 2001

Tropical storm 33W slowly developed just west of Kosrae on 13 December 2001, and then remained quasi-stationary for nearly 5 days (13 to 18 December). This unusual event can be attributed to a series of factors including interaction with a shear line extending toward the system from the northeast, a relatively weak, thin low/mid level subtropical ridge line, and a series of westerly wind bursts. Tropical Storm Faxai remained around Kosrae for several days before slowly moving in eastward motion. Faxai poured 10.74 and 24.76 in (27.3 and 62.9 cm) of rainfall upon Kosrae.

[Two deaths are attributed to Faxai on Kosrae. A young man named Chester Clarence was driving on the south side of the island when the top of a coconut tree came off and fell onto his vehicle killing him. There were reported to be other occupants in the car who were apparently unhurt in the accident. There was also a report of a man going up to a water catchment in Tofol to clear a blocked intake pipe. Indications were that he was pulled into the intake pipe and drowned when he tried to clear the obstruction.]

Faxai passed well to the north of Pohnpei after departing Kosrae. Faxai would later develop into a Super Typhoon.

Tropical Depression/Tropical Storm Dolphin 2015

On May 10, 2015, Tropical Storm Dolphin passed North East of Pohnpei with winds at approximately 80 mph causing an Emergency Declaration issued after damage to electrical, roads, uprooting of trees and crops and damaging more than 246 homes. 1 fatality was [officially] recorded.

Tropical Depression 01W 20 April 2023

Tropical Depression 01W formed south of Pohnpei and passed to the west of Pohnpei on April 19-20, 2023. The winds associated with the developing storms downed trees and powerlines. Power was lost island wide during the event.