You cause any sort of natural terrain (including water, forest, desert, tundra, and so on) to surge beneath your feet and safely propel you with devastating force over great distances. This wave of terrain undulates as it passes over the world, harmlessly lifting or stretching objects, creatures, and phenomena with a connection to nature but tearing through and damaging anything else it encounters. When you cast the spell you must choose the wave's type, either a tsunami or a swell. If you choose a tsunami, you create a 30-foot-high tidal wave of earth or water hurtling across the landscape that lasts for 1 round per level. If you choose a swell, you create a more controlled and gentle 5-foot-high wave that lasts for 1 hour per level. Regardless of its form or composition, the crest of the wave extends 10 feet in front of and behind you, and 5 feet per level to both your left and right. You can stand or sit on the crest of this wave without any fear of falling off it and can even lie down and sleep (or take any other actions you could take if standing on solid ground) as it travels. You can grant up to one additional creature per level the ability to safely accompany you on this wave.
When you first create the wave, you must choose its path by facing the direction you wish it to travel. Once you make this decision, you cannot change it. The wave, in either version, moves at eight times your base land speed. Any object, creature, or phenomena strongly connected to, or a part of, the natural world simply rises up and down with the wave as it passes, taking no damage or injury. However, anything else coming into contact with the wave takes either 6d6 points of bludgeoning damage (if the tsunami) or 1d6 points of bludgeoning damage (if the swell).
The wave damages any manufactured object or structure. On the Material Plane, it also damages any creature of the aberration, construct, outsider, or undead type, or with the extraplanar subtype. Creatures with the construct or undead type take double damage from the wave. Other creatures, or creatures with even one druid class level (regardless of their type), are considered a part of the natural world and are unaffected by the wave. Note that on other planes of existence, what is considered to be a part of the natural world may vary at the GM's discretion.
The wave can travel up or down the sides of natural features so long as it does not exceed a 45-degree angle. You cannot alter the dimensions of the wave as it travels. If the wave encounters terrain that it cannot incorporate into itself, the wave simply flows over or around the obstacle (creatures riding the wave are harmlessly displaced to the side to avoid the obstacle) unless the terrain occupies one-half or more of the area of the wave's crest. In such cases the spell ends in 1d6 rounds as the wave falters and collapses, unless its duration would normally cause it to expire prior to that.
The momentum of the wave carries you forward through this new terrain without any injury until it collapses, at which point you suffer the normal effects of the terrain in which you are deposited. Terrain the wave cannot incorporate includes anything primarily made from fire (such as lava), air (such as an open cliff face), or something man-made (such as a city).
You can only create the wave if standing on the ground. You cannot create it when underground or on terrain that it cannot incorporate.