Debris Flow — Tuolumne, California

2017-09-13 · near Tuolumne Meadows, Tuolumne, California

Event narrative

A Yosemite National Park employee reported a rock slide over Park Road near Hetch Hetchy.

Wider weather episode

The upper level low which had remained off the California coast for several days finally moved inland across Southern California on September 13 and produced enough instability over central California during the late afternoon for strong thunderstorms to develop over Yosemite National Park. One cell produced pea sized hail which accumulated to an inch in depth while flash flooding was reported in Hetch Hetchy. Meanwhile, an isolated thunderstorm in Bakersfield produced half an inch of rainfall in about one hour which set a new daily record.

View location on OpenStreetMap → (37.8370, -119.7194)

Source: NOAA Storm Events Database, event_id 720652. Narrative written by the NWS forecast office that issued the report.