Mountain Weather
Each year, approximately 2,000 hikers get lost
and searched for by Mountain Search and Rescue
units across the country.
and searched for by Mountain Search and Rescue
units across the country.
17% of victims report inclement weather
and visibility as the reason they lost the trail.
and visibility as the reason they lost the trail.
An essential part of climbing is preparedness in the event that the weather changes while you are on the mountain. Mountain weather has different considerations and influences than the weather in city environments. Mountains create and shape the weather that happens around the surrounding area. Therefore, it is important as a team member or solo climber to have a firm grasp on reading weather patterns, preparing ahead of time, and knowing how to backtrack in the thick of a weather event.
Many weather resources are available. Once in the field, your own observations allow you to monitor the progress of weather patterns that may determine the success of your trip and your personal safety. As you participate in the conditioning hikes and field sessions, you should obtain information about expected weather at your intended destination, then watch the sky for clues as to whether it is progressing as expected, and discuss the weather prospects with your leaders.
Lesson Objectives
After reading this page students should be able to:
Be able to find weather information in preparation for an alpine climb.
Give examples on how mountains and elevation affects the weather.
Know the signs of an upcoming electrical storm and what to do if you are caught in one.
Know how to navigate in a whiteout.
Describe weather patterns of the Pacific Northwest. NOAA (weather.gov)
Presentation: Mountain Weather
Pre-Trip Preparation
As you participate in the conditioning hikes and field sessions, always research information about expected weather at your intended destination. You and your team will observe the sky for clues as to whether it is progressing as expected, and discuss the weather prospects with your leaders before and throughout the hike. Your team will always be willing to turn around with Mazamas if the weather turns poorly.
Prior to your climb, the climb leader or assistant will send out a "Climbing Prospectus". This should also include a brief run down of the anticipated weather window, as well as other important information that may impact the climb. Although, it is still important to individually check weather conditions so that everyone is informed and aware of the weather risks. The weather windows of interest are the 72 hours leading up to and after your intended climb date.
Resources for Weather
Many weather resources are available. These are recommended starting points for those who are new to Mountain Weather Forecasts.
Snow-forecast
NOAA Portland
Windy.com: Shows wind patterns
PMR: Staying Safe
Trip Check: Shows road conditions in Oregon
Mountain Forecast: Check local small areas
When to check weather patterns:
Two days prior to trip—large and medium scale weather systems, projected weather for the next few days
One day prior to trip—large and medium scale weather systems, forecast
Day of the trip—current weather, forecast, freezing level, anticipated weather problems (high winds, avalanche danger, lightning)
During the trip—weather evolving as anticipated? Be alert for hazards
Two days after the planned trip - take note of the inclement weather that may come in early that is forecasted for the next day
Day of Climb: Field Observations
Know typical weather patterns, such as approach of fronts
Clouds: note types and progression of clouds over time
Winds: Surface wind shifts can signal frontal passages
Mountain specific weather: cloud caps, lenticular clouds, and halos and coronas around sun/moon
Altimeter/barometer: large changes over 3 hours signal approach of bad weather
Monitor weather predictions, such as NOAA weather radio, weather information on internet enabled cell phone
Be alert for development of hazards, precipitation, high winds, lightning, avalanche
Always check avalanche conditions when snow is present
Storm Indicators
The Pacific Northwest has weather that differs from the rest of the country. Become familiar with the weather patterns to prepare for climbs. Clouds can give you an indicator about what is happening at higher elevations. Observing visual weather patterns can assist your decisions.
Thunderstorm
Lightning drill: disperse party, away from isolated trees, off ridges/peaks, out of gullies, insulate yourself.
30–30 rule: Note seconds between flash and thunder. If less than 30 seconds, do lightning drill until 30 minutes after the last thunderclap. Sound of thunder travels 1 mile in 5 seconds.
Signs of immediate danger: crackling or buzzing sound, metal tools vibrating, hair standing on end, seeing a glow in the air around objects.
If struck: Approach victim only if safe. CPR and rescue breathing as necessary. Treat the "dead" first.\
Knowledge Check
Please complete the required knowledge check before moving on:
Chapter 16, Snow Travel and Climbing, Routefinding on Snow, p. 360-364
Chapter 16, Snow Travel and Climbing, "Safe Snow Travel" p. 364-365
Chapter 17, "Check Weather and Avalanche Forecasts", p. 373
Chapter 28, Mountain Weather, "Creating Custom Weather Briefings" p. 567
Chapter 28 , Mountain Weather, p. 558
Chapter 28, Mountain Weather, "Cold Fronts and Warm Fronts" p. 560