Heavy Snow — Grant Grove Area, California

2021-10-25 · Grant Grove Area, California

Event narrative

The Big Meadows SNOTEL picked up an estimated 12 inches of new snow.

Wider weather episode

A large upper level low pressure system in the Gulf of Alaska picked up an abundant amount of tropical moisture from the remains of Typhoon Namtheun on October 23. This large upper low then dropped southeast to off the Pacific Northwest coast on during the morning of October 24 then underwent rapid intensification during the afternoon of October 24 resulting in a strong surge of deep tropical moisture being pushed into central California by the evening of October 24. As the upper low tracked inland across the Pacific northwest on October 25, a cold front dropped southward through California bringing moderate to heavy precipitation to areas north of Kern County for 10-12 hours. Much of Yosemite National Park and Mariposa County picked up between 3 to 5 inches of liquid precipitation while 2 to 4 inches of liquid precipitation fell in the Sierra Nevada in Madera and Fresno Counties. Further south, 1 to 2 inches of liquid precipitation fell in the mountains of Tulare County while the Kern County Mountains generally picked up between half and inch and an inch of rainfall. Most of the San Joaquin Valley and West Side Hills also picked up between a half inch and an inch of rain while most of Merced County picked up between and inch to an inch and a half. The Kern County Deserts also picked up between a quarter and a half inch of rainfall. With most of the moisture from this system being of tropical origin, the snow level was above 9000 feet until the afternoon of October 25. The snow level lowered to 6000 to 7000 feet before the precipitation ended during the evening of October 25. Several SNOTEL stations measured between 9 and 15 inches of snow in 12 hours while a few stations above 9000 feet measured between 15 and 30 inches. There were also several stations which measured peak wind gusts between 58 and 70 mph ahead of the storm during the morning of October 25 or behind the cold front during the evening of October 25. Scattered thunderstorms developed over the San Joaquin Valley behind the cold front during the afternoon of October 25. One supercell produced a funnel cloud over southwestern Kings County then moved southeast into Kern County bringing heavy rainfall to the Lost Hills and Wasco areas. The precipitation tapered off by late evening and winds diminished by the morning of October 26 as the storm moved to the east of the area.

Source: NOAA Storm Events Database, event_id 982476. Narrative written by the NWS forecast office that issued the report.