Winter Storm — Centennial Mountains-island Park, Idaho

2025-03-15 to 2025-03-17 · Centennial Mountains-island Park, Idaho

Event narrative

A long period of snowfall brought 6 to 12 inches of snow through Island Park and Ashton Hill, with 12 to 24 inches north of Island Park towards Targhee Pass and West Yellowstone. Island Park measured 15.3 inches of snow, while the White Elephant SNOTEL measured nearly 45 inches of snow during the long duration event. Additionally, wind gusts occasionally reached 50-55 mph with a measured gust of 51 mph reported at the Henry's Lake ITD mesonet site. The combination of heavy snow and strong wind gusts led to the closure of Highway 20 from Ashton to the Montana border beginning the afternoon of the 16th.

Wider weather episode

A strong winter storm sequence, initially targeting the central ID mountains and Upper Snake Highlands with heavy snow. Strong wind gusts and accumulating snow then moved into eastern Idaho where the southeast highlands saw accumulating snow with slippery road conditions.

Source: NOAA Storm Events Database, event_id 1265211. Narrative written by the NWS forecast office that issued the report.