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Volcanoes

Any eruption in the Cascades is likely to have transportation and economic impact on Clackamas County indirectly.

Volcanic eruption

The Pacific Northwest lies on the "Ring of Fire," an area of active volcanic activity surrounding the Pacific Basin.   While only Mt. Hood and Mt. St. Helens are known to have had direct effects in the county in the past, any eruption in the Cascades is likely to have transportation and economic impact on Clackamas County indirectly.

The primary volcanic threat to lives and property in Clackamas County is depicted on the projected volcanic hazards map from Mt. Hood.  

These hazards can threaten our county from near or distant eruptions and include:

  • Mud and debris flows that can sweep down river valleys for tens of miles
  • Ash clouds that drift downwind with ash fall potentially causing a severe medical and transportation hazard.

US Geological Survey Cascade Range Current Update

Mount Hood Earthquake Swarm Information

Prepare
For tips on preparing for volcanic hazards go to: FEMA: Volcano

You can view volcanic activity at Mount Saint Helens at the United States Forest Service volcano cam web site.

Content provided by Emergency Management

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