Unseasonably cold temperatures and frost caused potentially significant damage to the 2018 Central Valley almond crop harvest by happening during the sensitive blooming phase. Temperatures in many locations reached or fell below the critical bloom temperature of 27. Some in the agricultural community were projecting frost damage ...worst since perhaps the 1970���s. (AgFax Tree Crops, Feb 26, 2018).
Snow fell in the Sierra, with unusually cold temperatures allowing snow down into the Sierra foothills, to elevations as low as 1400 feet. This caused some travel slow downs and delays in areas that usually don't see accumulating snow.

Winter Weather in MOTHERLODE/CAMPTONVILLE TO GROVELAND, CALIFORNIA
From 21-FEB-18 21:00:00 to 23-FEB-18 06:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Low elevation snow caused minor travel delays in the Motherlode. Weather spotters reported 1 of snow in Placerville, a trace at Shingle Springs(elevations 1400 feet), and a trace in Auburn (elevation 1500 feet).

Winter Weather in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 18-FEB-18 18:00:00 to 19-FEB-18 05:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Snow caused chain controls and travel delays in the Sierra, with road sensor data showing speeds briefly dropping to around 15 mph on I80 near pass level on the 19th and again on the 22nd. Caltrans reported 6 of snow at Soda Springs, 3 at Kingvale. Kirkwood Ski Resort reported 10 of new snow. Other reports include 6 at Bear Valley Ski Resort, 6 at Squaw-Alpine Ski Resort, 5 at Sugar Bowl Ski Resort, 4 at Tahoe Donner Ski Resort, and 2 at Dodge Ridge Ski Resort.

Winter Weather in NORTHEAST FOOTHILLS/SACRAMENTO VALLEY, CALIFORNIA
From 21-FEB-18 21:00:00 to 23-FEB-18 06:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Snow caused travel delays in the northeast foothills. A weather spotter reported a trace of new snow in Paradise. Lower Lassen Peak reported 4 of new snow.

Frost/Freeze in NORTHERN SAN JOAQUIN VALLEY, CALIFORNIA
From 19-FEB-18 02:00:00 to 21-FEB-18 08:00:00 (PST-8)
Property damage: 0.00K
Reported by: Mesonet

Almond trees were in critical bloom and early nutlet stage during the freeze/frost event. Damage has been projected as significant, but it is too early for specific details. Temperatures at Crabtree Weather Station reached 24 on the 19th, 22 on the 20th, 25 on the 21st. Temperatures at Stockton Metropolitan Airport reached 28 on the 20th and 21st.

Frost/Freeze in SOUTHERN SACRAMENTO VALLEY, CALIFORNIA
From 19-FEB-18 02:00:00 to 21-FEB-18 08:00:00 (PST-8)
Property damage: 0.00K
Reported by: ASOS

Almond trees were in critical bloom and early nutlet stage during the freeze/frost event. Damage has been projected as significant, but it is too early for specific details. Temperatures at Sacramento International Airport reached 26 on the 20th, 27 at Sacramento Mather Airport and at McClellan Airfield. Vacaville Nut Tree Airport reached 28 on the 20th and 21st.

Frost/Freeze in CARQUINEZ STRAIT AND DELTA, CALIFORNIA
From 19-FEB-18 02:00:00 to 21-FEB-18 08:00:00 (PST-8)
Property damage: 0.00K
Reported by: ASOS

Almond trees were in critical bloom and early nutlet stage during the freeze/frost event. Damage has been projected as significant, but it is too early for specific details. Temperatures at Fairfield- Travis Air Force Base reached 24 on the 20th, 26 on the 21st.

Frost/Freeze in CENTRAL SACRAMENTO VALLEY, CALIFORNIA
From 19-FEB-18 02:00:00 to 21-FEB-18 08:00:00 (PST-8)
Property damage: 0.00K
Reported by: ASOS

Almond trees were in critical bloom and early nutlet stage during the freeze/frost event. Damage has been projected as significant, but it is too early for specific details. Temperatures at Beale Air Force Base and Marysville reached 24 on the 20th, 26 at Oroville Municipal Airport and 27 at Chico Municipal Airport.

Frost/Freeze in NORTHERN SACRAMENTO VALLEY, CALIFORNIA
From 19-FEB-18 02:00:00 to 21-FEB-18 08:00:00 (PST-8)
Property damage: 0.00K
Reported by: ASOS

Almond trees were in critical bloom and early nutlet stage during the freeze/frost event. Damage has been projected as significant, but it is too early for specific details. Temperatures at Redding Municipal Airport reached 24 on the 19th, 26 on the 21st. Red Bluff Municipal Airport reached 26 on the 19th and the 21st.