POTENTIAL HAZARDS
If an eruption were to occur at Mt. Hood, there would be several hazards that could endanger human life as well as destroy buildings and other man-made sturctures. On this page I will describe the hazards that one could expect if an eruption of Mt. Hood happened.
Lahars
A lahar is a fast moving flow of mud, rocks and debris that occurs when water from glaciers is released due to a volcanic eruption. After flowing down the mountainside, lahars fill the valleys below. Because Mt. Hood is covered in glaciers, lahars would most likely cause massive amounts of damage to anything in their path. Depending on where the eruption takes place, lahars could move down any side of the mountain. If an eruption occured at Crater Rock, the place where scientists predict the next eruption to occur on the mountain, it would cause lahars to move down the west side of the mountain into the Sandy River and Zigzag River valleys. The lahar would hit many towns including Government Camp, Zigzag and Wildwood.
Hot Ash Flows
Hot ash flows are ash avalanches that are blasted out of the volcano during the eruption. Much like lahars, these move down the mountain at high speeds and usually destroy most things in their way. A hot ash flow could flow down any side of Mt. Hood depending on what side of the mountain the eruption happens. Hot ash flows have the potential to reach kilometers into river valleys so the same cities that are in the hazard zone for lahars are in the hazard zone for hot ash flows.
Landslides
Landslides are rocks that fall off the sides of the volcano and roll down the side of the mountain. These have the potential to hit ski lodges, houses and cabins on the side of the mountain and damage buildings and injure people at the base of the mountain. Landslides are most likely to occur where the eruption occured but there is a chance an eruption could trigger a landslide on any side of the mountain.
Ash Falls
Ash Falls occur when the rising ash from a volcano settles back to earth, covering the land in centimeters of ash. Much of the ash will fall to the earth near the volcano but some will be carried hundereds of miles and affect other communities. Much like the eruption of Mt. St. Helen's, if Mt. Hood erupted much of the ash would be dispersed around the mountain with the wind pushing some of it east. Several centimeters of ash could fall back to earth. This has the potential to cripple communities: making it hard to breath and basically shutting down transportation. Planes that fly through rising ash have suffered damage and could crash.
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Questions/Comments: peterjef@uwec.edu
Updated: April 25, 2005
