EF0 tornado, Perris, California, August 12, 2012

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF0

Date

August 12, 2012

Touchdown

3:30 PM PDT (22:30 UTC)

Lifted

4:45 PM PDT (23:45 UTC)

On the ground

75 minutes

Path length

0.5 miles (0.8 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

County

Riverside County

Touchdown point

33.769, -117.198

Lift-off point

33.769, -117.198

Record number

1208121630-01

These days were a continuation of the deep monsoonal flow that persisted over the area through much of the month. Thunderstorms developed each afternoon over the mountains, deserts and northern inland valleys, and quickly diminished by sunset with areas of rural, urban and flash flooding. Flooding activity on the 11th was focused around Big Bear and Victorville in San Bernardino County, as well as Campo in San Diego County. Thunderstorm activity also developed along the Elsinore Convergence Zone in eastern Riverside County. Thunderstorms in this area became severe and produced a couple damaging microbursts along with the small hail and heavy rain. Similar storms in the Elsinore area on the 12th produced a landspout and another damaging microburst. Significant flooding was also observed in the Forest Falls area on that day. Mostly minor urban flooding was observed in the upper deserts and Forest Falls again on the 13th.

A land spout tornado was associated with and southwest of the parent (non-supercell) thunderstorm that was over Nuevo, on the east side of Perris. The land spout appeared to be over the fields just east of or near Interstate 215. Separate wind damage from the parent thunderstorm was observed to the northeast over Nuevo on Menifee Road. |There was no apparent damage from the land spout itself. A spotter also sent in video of the land spout.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 19:59 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

The Santa Ana Mts radar (KSOX), 41 km away, was scanning. The volume nearest the touchdown began at 22:31 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2012 tornado in CaliforniaEvery tornado in California since 1950Warnings in force in California nowThe forecast where you are

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.