These events were the result of a large upper-level closed low over northern Baja, Mexico and featured four Santa Ana events, the strongest of which occurred in Orange County and southwest San Bernardino County with wind gusts 45 to 65+ mph and reported damage on December 1. These winds were strong enough to overturn several trucks, down power lines, reduce visibilities in dust and topple hundreds of large trees in Rancho Cucamonga (near Fontana, San Bernardino and Ontario), near the Cajon Pass along I-15. Rancho Cucamonga was declared a state of emergency by the State of California for the nearly 500 trees damaged. Overall, approximately 400 tons of debris was mitigated in the Rancho Cucamonga area.This area also suffered damage to the electrical infrastructure leaving many without power. As far as snow goes, 15 to 20 inches occurred in the San Bernardino County Mountains near Big Bear and Onyx Peak December 1 to 2, while only a dusting occurred in those mountains west of I-15. Much drier air moved into San Diego County on Saturday December 3, when the Santa Ana mountains and foothills had another surge of Santa Ana/offshore winds with gusts to near 60 mph and very low relative humidity. The final period of winds developed behind another system passing to our east on Monday, bringing wind gusts to 50 to 65 mph Monday night and Tuesday morning in the San Diego County mountains, and very low humidity.

High Wind in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 01-DEC-11 02:00:00 to 03-DEC-11 18:00:00 (PST-8)
Magnitude: 43.00 MS
Property damage: 160.00K
Crop damage: 0.00K
Reported by: Public

The Palm Avenue Elementary weather station in the city of San Bernardino recorded sustained northeast winds of 49 mph around 0700 PST on the 1st. A max gust of 70 mph was also recorded at that station at 0551 PST.
The Cal State San Bernardino mesonet station reported high winds between 0350 and 0550 PST. During this time, sustained winds of 40 mph were recorded along with gusts of 47 and 53 mph.
Numerous occurrences of wind damage near these stations were reported. An overturned box truck was blocking the slow lane of I-15 near Glen Helen Parkway.  Power lines and trees were downed near the city of San Bernardino. Power poles and lines were also down across 3rd Avenue near the Crafton Reservoir in Mentone.

Winter Storm in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 01-DEC-11 00:00:00 to 02-DEC-11 07:00:00 (PST-8)
Property damage: 9.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Snow began falling in the eastern sections of the San Bernardino County Mountains on the evening of November 30th, reached winter storm criteria sometime Thursday evening, December 1st and ceased later that night near midnight. Big Bear City received a storm total of 16 inches. Nearby Big Bear Lake received 18 inches, with some snow drifts reaching 2 to 3 feet. Onyx Peak received a storm total of 16 inches around 8200 feet.
Power lines were also downed in nearby Crestline on Crest Forest Drive at Scenic Drive.

Strong Wind in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 01-DEC-11 02:00:00 to 02-DEC-11 18:00:00 (PST-8)
Magnitude: 48.00 MG
Property damage: 600.00K
Crop damage: 0.00K
Reported by: ASOS

The Ontario Airport ASOS measured a wind gust of 55 mph around 0300 PST on the 1st. Visibility was reduced to 3 SM in blowing dust due to the strong wind.
In nearby Rancho Cucamonga, the slow lane of Highway 210 at Day Creek Boulevard was closed to upright a semi truck. Fences and hundreds of trees were downed in that area, some blocking roadways. Another big rig overturned in the center divide of Highway 210 at Beech Avenue, blocking the HOV lane until it could be up-righted.

High Wind in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 05-DEC-11 21:00:00 to 06-DEC-11 00:00:00 (PST-8)
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High winds began at the Boulder Creek SDGE mesonet site around 2100 PST on the 5th and ended around midnight on the 6th. During that time, several gusts over 58 mph were recorded including a peak gust of 65 mph around 2130 PST and another of 62 mph around 2300 PST.