Yellowstone's 500-Year Flood, June 2022: Evacuation and Recovery

From June 10 to 13, 2022, heavy rain and melting snow sent historic floodwaters through the northern part of Yellowstone National Park. The flood was classed as a 500-year event — a 0.2 percent chance in any year. Roads and bridges failed, mudslides blocked routes, the North Entrance Road was destroyed in several places, and the neighboring town of Gardiner, Montana, was badly damaged. The flood hit the region's ecosystem as well as its infrastructure.

The North Entrance Road, destroyed by high water. Credit: National Park Service.

The evacuation

• By 10 a.m. on June 13, the concessioner knew park infrastructure was badly damaged — including a severed Mammoth wastewater line spilling into the Gardner River.
• At 10:15 a.m., evacuation of the north loop began, followed by the south loop and concession facilities; Mammoth concession employees were moved south to reduce the wastewater flow.
• The park had begun evacuating visitors and closing entrances over the weekend, and inbound traffic stopped. On the morning of Tuesday, June 14, Montana declared a state of emergency.

About 10,000 visitors and 2,200 concession employees were accounted for and evacuated, much of it by the concessioners themselves, who relocated guests and staff to communities south, east and west of the park. Backcountry visitors were contacted on their way out. Mammoth lost power for more than 24 hours; one building still had power so seasonal employees could tell their families they were safe, and staff used emergency satellite phones.

Why the plan worked

In an emergency, the first priority is life safety and the second is stabilizing the incident. The concessioner followed its crisis management plan, modeled on the Federal Emergency Management Agency's. Staff had reviewed it regularly and knew their roles — important, because though a few had lived through the 1988 fires, most had never faced a disaster this big.

Recovery

Damage assessments started the day after the flood. By July 1 a temporary North Entrance Road, built with more than 20,000 tons of gravel, was open for one-way employee traffic. The park set up a reservation system for commercial tour operators to bring visitors in from the north during the road's travel windows. It saved more than 600 trips and was a lifeline for Gardiner, which was nearly empty; some hotels and small businesses survived on the group bookings. Concession staff ran its logistics.

The Park Service, the U.S. Geological Survey, concessioners and partners worked together on recovery. With the north road gone, the concessioner's laundry and main warehouse in Gardiner were cut off and had to move to Old Faithful; lodging and food service were hit hard, and delivery trucks had to detour around the destroyed areas.

Lessons for concessioners

• Discuss disaster plans often with the park's Concessions Management Specialist. Climate change has brought more natural disasters: know your area's vulnerabilities and prepare.
• Follow local laws, codes and regulations during an emergency.
• Review and revise the crisis plan, tell new staff about it and remind current staff where to find it. Ask: What vulnerabilities exist? What needs improving? Who is responsible for what? Where will visitors and employees go in an evacuation?
• Talk through roles and practice evacuation routes. FEMA's guides, vulnerability maps and National Risk Index can help.

Sources

Based on "Yellowstone Flooding: One Year Later," National Park Service, a work of the United States government in the public domain.