This event was an upper-level low that followed an inside slider trajectory, passing just north of the region and providing gusty north-northeast winds on the 22nd and 23rd, but little in the way of precipitation. The hardest hit areas were the Cajon Pass (I-15 through the San Bernardino Mountains) and areas below that in the Inland Empire which recorded wind gusts in the 45 to 65 mph range, with at least one gust in the 70s. Strong winds blew over several semi trucks, one causing injuries to the driver. Several high wind gusts were also reported nearby. As the winds turned more northeast-east on the 23rd into the 24th, San Diego County was affected as well, though most winds did not exceed high wind criteria. Instead the mountains in that area experienced wind gusts in the 40 to 55 mph range.

High Wind in SANTA ANA MOUNTAINS AND FOOTHILLS, CALIFORNIA
From 22-DEC-11 05:00:00 to 22-DEC-11 17:00:00 (PST-8)
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

High winds began between 0551 and 0651 PST on the 22nd at the Fremont Canyon RAWS and ended between 1451 and 1551 PST the same day. During this time, wind gusts of 70 mph or greater were measured each hour for approximately 7 hours, with a peak gust of 75 mph between 0751 and 0851 PST. Sustained winds were 50 mph or greater during many of these hours as well.

Strong Wind in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 22-DEC-11 04:00:00 to 22-DEC-11 08:00:00 (PST-8)
Magnitude: 49.00 MG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Mesonet

Winds began gusting over 40 mph at the Cal State San Bernardino mesonet station around 0350 PST on the 22nd and tapered off around 0850 PST the same morning. During that time a peak gust of 56 mph was recorded between 0700 and 0800 PST.
Several gusts between 45 and 55 mph occurred.  A sustained wind measurement of 43 mph was also reported for the hour between 0650 and 0750 PST.
Damages included a semi overturned on Interstate 15 near Fontana and another big rig overturned in strong winds on Interstate 210 near Rancho Cucamonga. A third truck was overturned on Interstate 15 near Devore by a strong wind gust. The driver of this box truck suffered minor injuries as a result.

Strong Wind in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 22-DEC-11 08:00:00 to 22-DEC-11 13:00:00 (PST-8)
Magnitude: 46.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: ASOS

Strong winds began at the Ontario International Airport between 0853 and 0953 PST on the 22nd and ended between 1153 and 1253 PST. During that time, several wind gusts between 44 and 46 mph were measured and a peak gust of 53 was recorded around 1120 PST.
A 50-foot empty semi tractor trailer overturned along Interstate 15 in nearby Mira Loma due to the strong winds.

High Wind in SANTA ANA MOUNTAINS AND FOOTHILLS, CALIFORNIA
From 23-DEC-11 03:00:00 to 23-DEC-11 09:00:00 (PST-8)
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

High winds began at the Fremont Canyon RAWS between 0651 and 0751 PST on the 23rd and ended between 0751 and 0851 PST. During that time, a peak gust of 63 mph was measured between 0751 and 0851 PST.
The nearby Santiago Peak mesonet station recorded a peak gust of 60 mph earlier that morning around 0400 PST.