Mudflow (aka lahar) damage can be costly and even deadly to the populace living along river drainage systems within and outside of Mount Rainier National Park. Lahars cannot be predicted, but USGS scientists and mathematicians have created scenarios demonstrating lahar speed, reach, and depth using a numerical simulation application called D-Claw.

The National Park Service has approved a proposal from the U.S. Geological Survey’s Cascades Volcano Observatory to improve the lahar detection system at Mount Rainier National Park. Mount Rainier is an active volcano with a history of large lahars (volcanic mudflows) that have previously impacted areas now populated both within and outside of the national park.

Despite more than two decades to get the task accomplished, and almost two years after a federal judge ordered the Federal Aviation Administration and National Park Service to get the job done by this summer, air tour management plans for eight national parks will not be completed on schedule, according to court documents filed by the two agencies.

Mount Rainier National Park has reopened public access to the Carbon River area of the park, reversing an emergency closure issued on November 15, 2021. However, you'll have to walk or bike in and be prepared to navigate around road and trail washouts and expect to encounter normal late winter hazards, including downed trees, snow, and changing weather conditions.