IAP 12.310
January 2008
Significant U.S. Weather Events
California Storm (Jan 3-5, 2008)
If you are from the Golden State, you know that January and February
are relatively unpleasant months. In most places, ~80% of their
annual precipitation occurs in these two months. This year, so
far, has been no different with the first major storm (Storm
of the Decade according to this researcher) coming 3 days into the
new year.
Here are some of the weather headlines that came from the NWS:
0909 AM HEAVY SNOW KIRKWOOD 38.70N 120.07W 01/06/2008 M132 INCH EL DORADO CA MESONET 8 TO 11 FEET STORM TOTAL. 7 TO 10 FEET IN THE LAST 48 HOURS. KIRKWOOD SKI RESORT. 1031 AM HEAVY SNOW MEYERS 38.86N 120.01W 01/06/2008 M90.0 INCH EL DORADO CA MESONET 7 TO 8 FEET SNOW STORM TOTAL. 30 TO 42 INCHES IN LAST 24 HOURS. 56 TO 90 INCHES IN LAST 48 HOURS. SIERRA AT TAHOE SKI RESORT. .LOS ANGELES COUNTY MOUNTAINS AND FOOTHILLS MOUNT WILSON CBS.................. 5.34 SANTA ANITA DAM................... 6.93 SAN GABRIEL DAM................... 8.62 MORRIS DAM........................ 7.28 BIG DALTON DAM.................... 7.16 SIERRA MADRE MAINT YD............. 6.11 TANBARK........................... 9.54 SAN ANTONIO DAM................... 5.61 EATON DAM......................... 6.02 MILL CK........................... 1.56 CHILAO............................ 1.51 MT BALDY FS....................... 7.51 WHITAKER PEAK..................... 2.41 WARM SPRINGS...................... 7.10 ACTON............................. 1.24 CAMP 9............................ 0.39 OPIDS CAMP....................... 11.37 1237 PM NON-TSTM WND DMG E NEVADA CITY 39.26N 121.02W 01/04/2008 NEVADA CA TRAINED SPOTTER NUMEROUS 2.5 TO 3 FOOT DIAMETER WHITE FUR AND CEDAR TREES DOWN VICINITY BANNER MTN AND MARYLAND/IDAHO ROAD INTERSECTION. SPOTTER WEATHER STATION MEASURED A 92 MPH WIND GUST AT 1237 PM.
A full (and I mean full) report of the
storm, it can be found here including tips on how to stay alive if
you're trapped in the mountains.
Let's look at the surface map at the beginning of the storm:
The cold front arrives with plenty of moisture. The green colors
indicate the intensity of the precipitation. Although this
figure does not delineate snow from rain, we can surmise that at the
top of the mountains, the temperature is sufficiently cold enough for
snow. As shown below, the next day, the radar shows an increase
in the precipitation intensity.
Finally, that next night, the front continued its southeastward track
and hit So. Cal as well, finalizing its California trek.
Why all this precipitation? Especially in the mountains?
Unlike the generally tranquil periods near California (an
example shown here), there were relatively very strong westerly
winds in the lower levels of the atmosphere as shown by the arrows in
the top left plot:
Combined with the direction and speed of the wind and the shape of the
mountain, this local feature helped intensify the vertical lift and
consequently the precipitation rate.
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