• Steam rises off of the colorful Mammoth Hot Springs Terraces. Photo courtesy Jacob W. Frank


    National Park ID,MT,WY

Thermal Activity Prompts Trail Closure

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Date: August 19, 2009
Contact: Al Nash, 307-344-2015
Contact: Stacy Vallie, 307-344-2015

National Park Service
U.S. Department of the Interior

Yellowstone National Park
P.O. Box 168
Yellowstone National Park, WY 82190
August 19, 2009    09-066    
Al Nash or Stacy Vallie (307) 344-2015


Thermal Activity Prompts Trail Closure in Yellowstone

Other trails reopened

Yellowstone’s Clear Lake Trail has been temporarily closed to protect the public from hazards associated with new thermal activity along the trail.

The "hot spots" along the trail indicate a heat source under the crust of the trail. These hot spots will be evaluated by park geology staff using thermal imaging and a ground survey.  The ground survey will include additional thermal infrared imaging and a direct measurement of ground temperatures. In select areas of concern, ground temperatures will be measured at a variety of depths to assess heat flow and potential areas of thin crust. 

Depending on the findings and before the trail can be reopened, it may be necessary to re-route the trail or build boardwalk over the hot spots.

The 1.5 mile-Clear Lake Trail is a popular route that overlooks both the Upper and Lower Falls along the Grand Canyon of the Yellowstone. The trail is located in an active thermal area.

Repairs to a section of boardwalk in the Back Basin of Norris Geyser Basin, to the stairs down Uncle Tom’s Trail along the South Rim of the Grand Canyon of the Yellowstone, and to the Wraith Falls Trail have been completed. All three trails have reopened to the public.

- www.nps.gov/yell -

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