A pair of winter storms associated with a vigorous, cold upper-low brought periods of high winds, heavy rain, and snow to the region from late on the 13th through the 17th. The first storm brought rain to the lower elevations and gusty winds and very heavy snow to the mountains and deserts. Blizzard conditions forced the closure of mountain highways while heavy rain caused a debris flow in the Santiago Burn Area. Snowfall accumulations from this first storm measured 31 inches at Big Bear Lake, 30 inches at Running Springs, and 24 inches at Forest Falls. The second storm on the 17th was notable for its significant rains in the low deserts and heavy snowfall in the mountains and high deserts. Heavy rain caused significant flooding in the Tijauna River valley. Surface offshore pressure gradients and mid-level easterly flow brought dry air into the region, resulting in widespread evaporative cooling and snow levels down to the desert floor. The winter storm dumped 20 inches of snow in Pinon Hills, 18 inches of snow in Hesperia, Lucerne Valley, Palomar Mountain, and Julian, 16 inches of snow in Idyllwild, 14 inches in Victorville, and even 4 inches in Shelter Valley. Local snowfall amounts in excess of 2 feet occurred in the San Bernardino Mountains. Total snowfall accumulations at Big Bear Lake for the 5 day period ending on the 17th was an impressive 54 inches.

Heavy Snow in APPLE AND LUCERNE VALLEYS, CALIFORNIA
From 15-DEC-08 07:00:00 to 15-DEC-08 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Snow began in Lucerne Valley around 1000 PST. By 1130 PST 4 inches of snow had accumulated. Snowfall ended around 1900 PST, with a total accumulation of 9 inches.

Heavy Snow in RIVERSIDE COUNTY MOUNTAINS, CALIFORNIA
From 15-DEC-08 06:00:00 to 15-DEC-08 13:56:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Snow began to fall in Idyllwild around 0600 PST. By 1400 PST a total of 9 inches had accumulated and the snow had turned to rain.

Winter Storm in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 15-DEC-08 02:00:00 to 15-DEC-08 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The first in a series of significant winter storms dumped 2-3 feet of new snow in the San Bernardino Mountains. Total snowfall accumulations measured 31 inches at Big Bear Lake, 30 inches at Running Springs, and 24 inches at Forest Falls. Most mountain highways were closed because of heavy snow and trapped motorists. Approximately 25 vehicles were stranded on Highway 330 near Running Springs and another 9 vehicles were stranded on Highway 38 near Cedar Falls.

Winter Storm in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 17-DEC-08 00:00:00 to 17-DEC-08 22:00:00 (PST-8)
Property damage: 50.00K
Crop damage: 0.00K
Reported by: COOP Observer

The San Bernardino County Mountains received 18-24 inches of new snow from a significant winter storm. The Big Bear Lake Fire Department measured 23 inches of new snow from this storm, bringing their 5 day total accumulation to an impressive 54 inches. Interstate 15 through the Cajon Pass was shutdown for 24 hours due to heavy snow, the longest closure of that stretch of I-15 in more than 15 years.

High Wind in SANTA ANA MOUNTAINS AND FOOTHILLS, CALIFORNIA
From 17-DEC-08 10:30:00 to 17-DEC-08 16:30:00 (PST-8)
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Gusts over 58 MPH were measured by the Fremont Canyon RAWS between 1030 and 1630 PST. Sustained winds of 48 MPH with gusts to 69 MPH was measured at 1230 PST.

High Wind in APPLE AND LUCERNE VALLEYS, CALIFORNIA
From 15-DEC-08 18:51:00 to 15-DEC-08 19:51:00 (PST-8)
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Onshore flow caused gusty downslope winds in the deserts. A peak wind gust of 59 MPH was measured by the Burns Canyon RAWS.

High Wind in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 17-DEC-08 11:12:00 to 17-DEC-08 13:12:00 (PST-8)
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

A wind gust of 72 MPH was measured by the Beaumont RAWS.

Flash Flood in SAN DIEGO, CALIFORNIA
From 17-DEC-08 11:30:00 to 17-DEC-08 15:30:00 (PST-8)
Location: SAN YSIDRO
Flood cause: Heavy Rain
Property damage: 250.00K
Crop damage: 610.00K
Reported by: Newspaper

Significant flooding in the Tijuana River Valley resulted in the deaths of a Tijuana man and numerous ranch and farm animals. At least 21 people had to be rescued, including 6 by helicopter. Three men were taken to a hospital and treated for hypothermia. An estimated 70 horses were also rescued. Three horses drowned before they could be rescued and another horse was later euthanized due to a leg injury. Fifteen goats and an unknown number of dogs also died in the flood. One farmer lost $600,000 dollars worth of his crop while another lost $10,000 dollars worth of watermelons. The one human death occurred outside the forecast area in Tijuana, Mexico. The flash flood occurred when both the Tijuana River and a nearby flood control channel became dammed with with sediment, trash, and other debris.

Winter Storm in RIVERSIDE COUNTY MOUNTAINS, CALIFORNIA
From 17-DEC-08 00:00:00 to 17-DEC-08 22:00:00 (PST-8)
Property damage: 25.00K
Crop damage: 0.00K
Reported by: COOP Observer

The Riverside County Mountains received in excess of 16 inches of snow from a significant winter storm. The Idyllwild Fire Department measured 16 inches of new snow from this storm, however higher amounts probably fell in nearby areas where the flow was favorable for heavier snowfall. Tree damage resulted in power outages in Idyllwild and Fern Valley.

High Wind in APPLE AND LUCERNE VALLEYS, CALIFORNIA
From 13-DEC-08 12:05:00 to 13-DEC-08 17:51:00 (PST-8)
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Onshore flow and strong winds across the mountains caused very gusty downslope winds over the deserts. Wind gusts up to 72 MPH were measured by Burns Canyon RAWS. A trained weather spotter also measured a 62 MPH wind gust at Lucerne Valley.

Heavy Rain in ORANGE, CALIFORNIA
From 15-DEC-08 08:00:00 to 15-DEC-08 10:30:00 (PST-8)
Location: DISNEYLAND
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Newspaper

Shortly after 0900 PST, the roof of a classroom partially collapsed due to heavy rain. Fourteen people, ages 17 to 50, were taken to the hospital with minor injuries.

Winter Storm in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 17-DEC-08 00:00:00 to 17-DEC-08 22:00:00 (PST-8)
Property damage: 100.00K
Crop damage: 0.00K
Reported by: NWS Employee

Significant snowfall was observed above 3000 ft in the San Diego Mountains with 18 inches measured at Palomar Mountain and Julian. The heavy snow caused widespread tree damage between 3500-4000 ft. Live Oaks were especially hard hit due to their large growing habit and because they keep their leaves year-round. Some limbs and trees fell onto structures and roadways. A few tool sheds were also damaged by the weight of the snow.

Winter Storm in APPLE AND LUCERNE VALLEYS, CALIFORNIA
From 17-DEC-08 00:00:00 to 17-DEC-08 22:00:00 (PST-8)
Property damage: 50.00K
Crop damage: 0.00K
Reported by: COOP Observer

The San Bernardino County Deserts received 6-20 inches of snow from a significant winter storm. The COOP observer in Hesperia measured 18 inches of snow. Elsewhere, trained weather spotters measured 20 inches of snow in Pinon Hills, 18 inches of snow in Lucerne Valley, 14 inches of snow in parts of Victorville, 12 inches of snow in Adelanto, and 7 inches of snow in Apple Valley. Interstate 15 through the Cajon Pass was shutdown for 24 hours due to heavy snow, the longest closure of that stretch of I-15 in more than 15 years.

Flash Flood in ORANGE, CALIFORNIA
From 15-DEC-08 10:30:00 to 15-DEC-08 11:30:00 (PST-8)
Location: MODJESKA
Flood cause: Heavy Rain / Burn Area
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Heavy rain in the Santiago Burn Area caused mud and debris flows in Modjeska Canyon. Many of the roads and yards that were buried in mud by this debris flow were impacted by similar debris flows last winter. The amount of mud and rock left in the wake of the debris flow was extensive but damage to roads and property was minor.