Trinity storm history

An atmospheric river aided in heavy rain development across the River Complex burn scar. One or possibly more debris flows occurred as a result. Removal, protective measures, and repair costs from this debris flow are estimated to be $3.2 million.

Culvert failures and slipouts along Highway 36 in Trinity County from mile post 2 to 14.

A landslide on Highway 299 blocked both lanes of the highway and resulted in a full closure.

Report of half-inch to one-inch sized hail near Trinity Lake.

Slide reported in westbound lane of Hwy 299, 2 miles east southeast of Del Loma, CA. Lat. 40.76N, Long. -123.29W.

A rock slide blocking both lanes of SR299, 1 mile south of Burnt Ranch, CA. Lat. 40.81N, Long. -123.47W.

A landslide covering one lane of Pattison ranch road, 1 mile west northwest of Big Bar, CA. Lat. 40.74N, Long. -123.27W.

Huge boulder on eastbound lane of hwy 299, 1 mile north of Big Bar, CA. Lat. 40.74N, Longt. -123.25W.

Highway 299, landslide reported 1 mile east northeast of Big Bar, CA. Lat. 40.74N, Long. -123.22W.

A section of Pelletreau Ridge Road and Wintoon Flat Road washed out and closed, 2 miles southwest of Hyampom, CA. Lat. 40.59N, Long. -123.48W.

Rock slide reported in one lane of hwy 299, 2 miles east of Helena, CA. Lat. 40.77N, Long. -123.09W.

A rock/mud slide occurred across hwy 299, between Cedar Flatt and Del Loma. Lat. 40.80N, Long. 123.38W.

A slide is blocking 1 lane, 2 miles south southeast of Burnt Ranch, CA. LAT. 40.79N, LONG. -123.45W.

Boulder the size of a vehicle on the road 5 miles southwest of Douglas City, CA. LAT. 40.60N, LONG. -123.01W.

Partial slide block the road about 2 miles east of Helena, CA. LAT. 40.77N, LONG. -123.08W.

Rocks and debris are in both lanes, blocking the westbound lane completely, 3 miles east of Big Bar, CA. LAT. 40.74N, LONG. -123.19W.

Landslide blocking the eastbound lane with mud and rocks in both lanes, 1 mile east of Douglas City, CA. LAT. 40.65N, LONG. -122.94W.

Landslide blocking 1 lane of hwy 299 1 mile north northeast of Big Bar, CA. LAT. 40.74N, LONG. -123.25W.

A landslide blocking the westbount lane of the 299 2 miles east of Helena, CA. LAT. 40.77N, LONG. -123.09W.

Large rocks across the roadway as reported by law enforcment, 1 mile west northwest of Del Loma, CA. LAT. 40.79N, LONG. -123.35W.

Rock and mud slide across HWY 36 due to heavy rain.

Rock slide across roadway.

Earth slide partially covering HWY 299.

Heavy rain caused a landslide across HWY 299 east of Helena.

Rocks and debris across HWY 299 near Hawkins Bar due to heavy rainfall.

Heavy rain caused a rockslide that spread across Highway 299 leading to a truck accident.

A thunderstorm set up over the a portion of the 2021 River Complex Burn Scar and caused a debris flow as reported by Trinity County OES on Coffee Creek on 2 August. The debris flow caused Coffee Creek Road to be unpassable. A Flash Flood Warning was issued shortly after 03/0110Z.

Minor flooding on county road due to 4 inches of rain over a 24 hour time period.

Spotter report of 2.47 inches of rain near Big Bar.

Thunderstorm wind damage 3 miles south of Weaverville. Roads were blocked due to tree damage. Power was out as well. Measured gust from RAWS station was 43 mph. City property was also damaged due to wind driven hail.

Estimated quarter size hail and thunderstorm wind gusts from 30 to 40 mph observed at the Douglas City store.

Heavy rain aided in a rock slide on Highway 299. West bound lane was closed as a result.

Rock slide with wheel-barrow size rocks on Highway 299.

Large boulder along Highway 299 at mile marker TRI 26.

Highway 36 closed due to rock slide 3 miles west of Forest Glen.

Rock slide at 1240 Highway 36 near Mile marker TRI 12.

Rock slide at 1500 Highway 36 at mile marker TRI 15.

Highway 299 had one way traffic control in effect due to a rock slide occurring across the highway.

Heavy rainfall accumulation of 4.5 inches. Thunder occasionally heard during the rain event.

Twenty-four hour rainfall total of 3 inches.

Heavy rain led to mud/dirt/rock slide at Big French Creek Road.

Estimated the largest hail stones to be the size of a quarter. Storm lasted from somewhere between 4 and 430 until 5 PM. Rain was very heavy.

Marble to quarter size hail along with locally heavy rain.

Marble to quarter size hail reported by trained spotter. Time and location approximate. Locally heavy rain as well.

Undermined hill and slip-out near mile post 15 on Highway 3.

A thunderstorm impacted Big Bar and produced a hail event that lasted for 30 minutes. The estimated hail size was as large as a golf ball. The hail covered the ground to a depth of 2 inches with drifts up to 6 inches deep.