A deep layer of monsoonal moisture pushed northwest and north into California, Sierra, and western Nevada in a southerly upper flow that marked the western margins of an area of strong high-pressure ridging into the Great Basin region.  Thickening mid-level moisture coupled with steep afternoon lapse rates and warmer surface heating initiated deep columns of slow-moving moisture-laden showers and thunderstorms with torrential rains over the 2021 Tamarack burn scar. This resulted in widespread flash flooding and debris flows in Alpine County CA that created a number of impacts. Rainfall rates of 2.22 inches per hour were observed during the peak of the storm in Markleeville, CA which corresponds to at least a 500 year recurrence interval and possibly 1000 year, per NOAA 14 atlas.

Debris Flow in DOUGLAS, NEVADA
From 04-AUG-22 17:00:00 to 04-AUG-22 18:00:00 (PST-8)
Location: MOTTSVILLE
Flood cause: Heavy Rain
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Department of Highways

NDOT and CHP reported mud, dirt, and rock in roadway making Jackson Ranch Road impassible.

Flash Flood in WASHOE, NEVADA
From 05-AUG-22 14:02:00 to 05-AUG-22 14:02:00 (PST-8)
Location: HUFFAKERS HILLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

It was reported on August 5 by a Washoe County official that flash flooding occurring on August 4 closed the lower Whites Creek trail in Galena Creek Park from Timberline Road to Thomas Creek Road due to extensive trail damage from recent flooding. It was also reported that rainfall amounts between 2.5 and 3 inches occurred in the area on Thursday 8/4.

Heavy Rain in WASHOE, NEVADA
From 04-AUG-22 17:00:00 to 04-AUG-22 18:00:00 (PST-8)
Location: WASHOE CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet station WCTN2 located 5.1 mi N of Washoe City, and mesonet station GALN2 (Galena) located 4.0 mi NNW of Washoe City reported rainfall totals of 1.81 and 2.75 inches respectively.

Heavy Rain in WASHOE, NEVADA
From 03-AUG-22 18:45:00 to 03-AUG-22 19:45:00 (PST-8)
Location: (RNO)CANNON ARPT REN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

ASOS station (KRNO) located at the Reno-Tahoe International airport recoded a one hour rainfall total of 1.22 inches between 6:45PM and 7:45 PM LST.

Heavy Rain in DOUGLAS, NEVADA
From 04-AUG-22 12:00:00 to 04-AUG-22 17:25:00 (PST-8)
Location: CENTERVILLE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained weather spotter located 3.0 miles WSW of Gardnerville Ranch reported a total rainfall amount of 3.1 inches from 12:00 PM to 17:25 PM LST. Spotter also reported flooding issues along Foothill Road in the area.

Heavy Rain in DOUGLAS, NEVADA
From 04-AUG-22 12:00:00 to 04-AUG-22 18:33:00 (PST-8)
Location: DOUGLAS CO ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained weather spotter located 1.0 miles W of Johnson Lane reported a total rainfall amount of 2.5 inches that fell during the period from 12:00 PM to 18:33 PM.

Heavy Rain in WASHOE, NEVADA
From 05-AUG-22 18:00:00 to 05-AUG-22 19:00:00 (PST-8)
Location: GERLACH
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet stations Fox Mountain (FOXN2) located 27 mi NNW of Gerlach, NV, and Juniper Springs (JSPN2) located 36 mi S of Vya, NV, both reported rainfall totals of 0.59 inches and 0.83 inches respectively.

Flood in DOUGLAS, NEVADA
From 04-AUG-22 13:00:00 to 04-AUG-22 14:00:00 (PST-8)
Location: CENTERVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter located 3.0 mi WSW of Garnerville Ranch, NV, reported some mud over foothill road, and also some minor flooding impacts. Rainfall total over a 1.5 hour period was reported as 1.98 inches.

Heavy Rain in LYON, NEVADA
From 03-AUG-22 17:00:00 to 03-AUG-22 18:00:00 (PST-8)
Location: DAYTON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter located 2.0 mi ESE of Six Mile Canyon reported a one hour total rainfall amount of 1.56 inches between 5:00 PM and 6:00 PM LST.