A thunderstorm developed near Redlands around 3:30 PM and quickly became severe as it moved south-southwest toward Moreno Valley along the Elsinore Convergence Zone. This storm produced large swaths of hail, flash flooding, and at least four tornadoes.

Flash Flood in RIVERSIDE, CALIFORNIA
From 22-MAY-08 15:00:00 to 22-MAY-08 15:40:00 (PST-8)
Location: EL CASCO
Flood cause: Heavy Rain
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Newspaper

Flash flooding caused serious damage to several residential neighborhoods in rural northeastern Moreno Valley between Moreno Beach Dr and Redlands Blvd. City building and safety inspectors declared one home unsafe to occupy and at least four others damaged near Locust Ave north of State Highway 60. A few miles south at the 29000 Block of Stevens Ave, several more homes were damaged by ���major��� flooding. Elsewhere, flash flooding forced the closure of San Timoteo Canyon Rd, Live Oak Canyon Rd, and portions of Alessandro Rd. Fire officials received a total of 28 reports of flooded residences due to the thunderstorm.

Tornado in RIVERSIDE, CALIFORNIA
From 22-MAY-08 15:30:00 to 22-MAY-08 15:36:00 (PST-8)
Location: MARCH AFB
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Observations from KRIV indicate that this tornado touched down at 4:30 PM approximately four miles southeast of the March ARB and was on the ground for six minutes. No reports of damage were received and this tornado was rated EF-0 tornado. The exact path of this tornado is not known.

Hail in RIVERSIDE, CALIFORNIA
From 22-MAY-08 14:55:00 to 22-MAY-08 15:50:00 (PST-8)
Location: CALIMESA
Magnitude: 0.88 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

A tornadic thunderstorm left a swath of hail up to several inches deep from north of Moreno Valley to Perris. Snow plows were called out to clear the hail from Interstate 10. While most of the hailstones were pea-size, several reports of marble to nickel size hail were received from Moreno Valley just prior to the tornadoes. The larger hailstones left holes in awnings and stripped leaves from trees.

Tornado in RIVERSIDE, CALIFORNIA
From 22-MAY-08 15:50:00 to 22-MAY-08 15:58:00 (PST-8)
Location: VAL VERDE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Photos and video of the EF-2 tornado all show a separate tornado occurring in its vicinity at the same time. Based on photographic evidence and eyewitness accounts, this separate tornado would be the third tornado produced by the storm. The exact path is not known, however several videos indicate that this tornado was just west of Interstate 215 in close proximity to the Riverside National Cemetery. No reports of damage were received and this tornado was rated EF-0.

Tornado in RIVERSIDE, CALIFORNIA
From 22-MAY-08 15:42:00 to 22-MAY-08 16:03:00 (PST-8)
Location: MARCH AFB
Tornado F-scale: EF2
Property damage: 350.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Observations from KRIV indicate that this tornado touched down on March Field at 4:42 PM, traveled approximately three miles in a west-southwest direction for 21 minutes, and had a max width of 75 yards. As the tornado crossed Interstate 215, a semi-truck was lifted 30 to 40 feet into the air and nine empty BNSF railroad cars were derailed. The driver of the semi had to be extricated using the ���jaws of life��� and was hospitalized for over a month due to moderate head injuries. The tornado also damaged the roofs of several homes and a trailer on Kuder Ave. It should be noted that another tornado developed nearby while this tornado was in progress. Based on input from Dr. Kisho Mehta and Tim Marshall, damage to the rail cars was consistent with wind gusts up to 120 mph, or an EF-2 tornado. This is the first EF-2 tornado in California since the new scale was implemented in February 2007, and the first F2 tornado in California since the 1998 Sunnyvale tornado.

Tornado in RIVERSIDE, CALIFORNIA
From 22-MAY-08 16:40:00 to 22-MAY-08 16:45:00 (PST-8)
Location: ALESSANDRO
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained weather spotter from the Lake Elsinore area captured video of a tornado between 5:40 ��� 5:45 PM. This tornado occurred in an unpopulated area near the Gavilan Hills between Woodcrest and Lake Elsinore, however the exact path is unknown. This was the fourth and final tornado produced by the storm. No reports of damage were received and this tornado was rated EF-0.