Low Probability, High Consequence
"We call it low probability, high consequence," Steven Bailey, Pierce County, Washington's director of emergency management told Ultimate Explorer. "It's a low probability it's going to occur in our lifetime. But if and when it does, the consequences are going to be huge."
Given the potentially devastating effects of a lahar, authorities in Washington stand on alert. The USGS, in cooperation with the University of Washington, monitors Mount Rainier for signs of volcanic activity and lahar flows.
The agency has created a lahar roadmap based on historic slide paths and is working with local governments to implement a response plan. USGS and the Pierce County Department of Emergency Management have installed a lahar-detection and warning system that utilizes acoustic flow monitors. These devices can detect the ground vibrations caused by lahars. An automated system would alert emergency management agencies.
The system, which only issues an alert once a lahar begins, gives some warningbut not much. Some communities would have 40 minutes to react. Other areas would have even less warning.
Experts say the safest course for those who found themselves in harm's way would be to get to high ground as soon as possible. Without time to evacuate, valley residents should scramble up the valley wall. As little as 50 or 100 feet (15 to 30 meters) could make all the difference.
Emergency professionals like Puyallup, Washington, fire chief Merle Frank know that getting people to safety under short notice would be a daunting challenge.
"We [would] have an hour and probably fifteen, twenty minutes to evacuate 35,000 people," he told Ultimate Explorer.
A key challenge for emergency response officials is to educate residents about the threat posed by lahars.
"Hurricane season is a season of every year," Bailey, told Ultimate Explorer. "Tornado season is a season of every year. This hazard has such a long time span that it's hard for people to relate to."
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