Warm weather combined with cold and fast moving area waterways lead to 5 deaths across the region in the month of May.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS STO wrote it up.
Warm weather combined with cold and fast moving area waterways lead to 5 deaths across the region in the month of May.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at May 15, 12:42 PM PST, 6 hours 18 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 142 PM PDT Sat May 15 2021 .SYNOPSIS... Cooler temperatures continue, with slightly warmer temperatures returning early next week. Scattered showers and thunderstorms are possible this weekend, mainly over the mountains, though a few storms may migrate into the lower elevations late this afternoon and this evening. && .DISCUSSION... This afternoon and tonight the focus will be on the low pressure area that is currently over Northern San Joaquin valley and where showers and thunderstorms develop. Currently as the low moves southward this evening wrap around moisture will be carrying any activity westward towards the valley. The best chances for any activity within the valley remains north of Sacramento. Thunderstorms will be capable of brief heavy rain, small hail and gusty winds. As the low moves southward into the Southern San Joaquin valley late tonight chances of showers moving into the valley will increase over the Northern San Joaquin valley while decreasing further north. Winds through the Delta will continue to be breezy overnight but expecting a lower marine layer so chances of low clouds are not as great as this morning. That said still think we may see some into the Delta and perhaps eastern side of the valley and foothills form by morning. By Sunday afternoon the low will be centered near Las Vegas with wrap around moisture continuing. Currently it looks like activity could reach the foothills but not the valley. Warmer temperatures are expected over the northern valley with slightly cooler temperatures over the southern areas. As the low moves east Sunday night activity will diminish. The Delta breeze looks to be stronger and we should have a slightly higher marine layer than tonight so low clouds will have a better chance of advecting into the Sacramento region by Monday morning. Monday will be dry other than a chance for some afternoon pop up showers and thunderstorms near the crest from near I-80 southward. Temperatures will be warmer for most areas with slight cooling over the north end of the valley and surrounding mountains. Weak ridging on Tuesday will keep the area dry with some warming of temperatures. && .EXTENDED DISCUSSION (Wednesday THROUGH Saturday)... No major changes to the extended forecast as confidence remains high in a cooler weather pattern for NorCal. Max temps are forecast to run some 5 to 15 degrees below normal during the period, while min temps look to be about 2 to 10 degrees below normal. Thursday still looking to be the coolest day out of this period with highs generally in the 70s for the Valley, the 60s for the foothills, and 40s and 50s for the mountains. In addition to the cooler weather, models and ensembles are hinting at renewed chances for showers. The showery regime is especially favored over the higher terrain due to topographic lift and forcing. Snow showers may occur over the higher elevations, above 5000 or 6000 feet, of the Sierra as well, mostly likely Thu/Fri. Ensembles show a little disagreement about how far east the trough is forecast to move over the weekend, but drier flow and warmer temps look likely. && .AVIATION... Localized MVFR/IFR conditions possible in showers and thunderstorms over the foothills, mountains, and northern Sacramento Valley this afternoon and into the evening, otherwise, VFR conditions. Onshore winds from the W to SW up to 15-20 kt around the Delta with gusts to 30 kt possible in the Delta after 00z Sun. Elsewhere, winds generally below 10 kt. && .STO WATCHES/WARNINGS/ADVISORIES... None. &&
Special Weather Statement
National Weather Service Sacramento CA
247 PM PDT Sat May 15 2021
CAZ013-152230-
Shasta Lake Area / Northern Shasta County-
247 PM PDT Sat May 15 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL SHASTA COUNTY...
At 246 PM PDT, a strong thunderstorm was located over Pollard Flat,
or 20 miles north of Shasta Dam, moving southwest at 20 mph.
Winds in excess of 30 mph and pea size hail are possible with this
storm, as well as brief, heavy rainfall.
Locations impacted include...
Lakehead-Lakeshore, Lakehead, Vollmers, Sims, Pollard Flat and
Fisher.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
LAT...LON 4095 12226 4079 12261 4085 12265 4090 12260
4092 12262 4098 12260 4101 12253 4106 12252
4107 12254 4109 12252 4109 12248 4113 12238
TIME...MOT...LOC 2146Z 066DEG 19KT 4100 12238
RoweSpecial Weather Statement National Weather Service Sacramento CA 636 PM PDT Sat May 15 2021 CAZ015-016-066-068-160215- Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Central Sacramento Valley-Western Plumas County/Lassen Park- 636 PM PDT Sat May 15 2021 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN TEHAMA AND NORTHWESTERN BUTTE COUNTIES... At 636 PM PDT, a strong thunderstorm was located near Butte Meadows, or 20 miles south of Mineral, moving southwest at 40 mph. Winds in excess of 40 mph and pea size hail are possible with this storm. Locations impacted include... Richardson Springs. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. LAT...LON 4021 12164 4004 12155 3978 12183 4016 12217 TIME...MOT...LOC 0136Z 049DEG 37KT 4009 12168 Rowe
Special Weather Statement National Weather Service Sacramento CA 652 PM PDT Sat May 15 2021 CAZ015-066-068-160245- Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Western Plumas County/Lassen Park- 652 PM PDT Sat May 15 2021 ...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL TEHAMA AND SOUTH CENTRAL SHASTA COUNTIES... At 652 PM PDT, a strong thunderstorm was located near Whitmore, or 9 miles northwest of Shingletown, moving southwest at 45 mph. Winds in excess of 30 mph and pea size hail are possible with this storm. Locations impacted include... Redding, Shingletown, Palo Cedro, Anderson, Whitmore, Inwood, Millville, Paynes Creek and Manton. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. LAT...LON 4075 12199 4066 12177 4028 12193 4055 12243 TIME...MOT...LOC 0152Z 032DEG 39KT 4059 12199 Rowe
Special Weather Statement National Weather Service Sacramento CA 742 PM PDT Sat May 15 2021 CAZ015-066-068-160330- Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Western Plumas County/Lassen Park- 742 PM PDT Sat May 15 2021 ...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN TEHAMA AND SOUTHEASTERN SHASTA COUNTIES... At 741 PM PDT, a strong thunderstorm was located over Paynes Creek, or 12 miles south of Shingletown, moving southwest at 25 mph. Winds in excess of 30 mph and pea size hail are possible with this storm. Locations impacted include... Shingletown, Lyonsville, Paynes Creek and Manton. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. LAT...LON 4051 12190 4049 12170 4003 12174 4028 12219 TIME...MOT...LOC 0241Z 029DEG 23KT 4032 12190 Rowe
2 cold/wind chill. Local standard time, as filed.
A 17 year old was swimming in the American River in Rancho Cordova, at the Elmanto river access point. He went under the water and never surfaced; however, the body was recovered. CNRFC gauges near Rancho Cordova had water temperatures in the low to mid 60s.
Three people went overboard on a boat in the Delta, with 2 people surviving and making it to shore. The third person is a 22 year old male who went missing near the Mokelumne River Bridge and is presumed to be deceased. Rescue officials noted that the deceased person was not wearing a lifejacket. CNRFC gauges near the Delta had water temperatures in the low to mid 60s.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Cold/Wind Chill, Southern Sacramento Valley | 2021-05-15 | 17 | Male | In Water | Direct |
| Cold/Wind Chill, Carquinez Strait and Delta | 2021-05-16 | 22 | Male | In Water | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, May 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 963156, 963157.