Rain Makes Dent in California Drought/Record Cold Winter Statistics

Rain Makes Dent in California Drought/Record Cold Winter Statistics

A deep Pacific low-pressure system cruised the California coastline this past weekend pounding southern California with heavy rain, the first such in over a year. The entire state also saw decent rainfall as well. How has this storm changed the precipitation deficits and reservoir levels? Also, the statistics are in for the climatological winter of 2013-2014. Here is a list of cities that endured their top 10 coldest such on record.

California Rainstorm

Although the entire state saw some much needed precipitation this past weekend, it was the southern third that was most affected. Over 14” of rain fell in a couple of locations in the San Bernardino Mountains north of Los Angeles and even 4.52” fell in Downtown L.A.: more rainfall in three days then had accumulated in the 14 months preceding this storm, and changing their water season precipitation deficit from 11% of normal last week to 50% now! Here are some of the statistics for the Los Angeles area:



Table/graphic from NWS-Los Angeles.

In central California the heaviest rainfall was in the St. Lucia Mountains near Big Sur where 12.99” of rainfall was measured at Mining Ridge. Places north of Monterey received modest amounts of precipitation such as the 2.04” in downtown San Francisco and 3.73” in Redding (in the northern end of the Sacramento Valley). Sacramento itself picked up 1.49”. Here is a comparison of how the storm affected the precipitation deficits at major cities across the state (arranged geographically from north to south).

California Seasonal Precipitation (July 1-February 25th and March 2nd)



Comparison of seasonal precipitation prior to the storm (as of February 25th top table) to after the storm (as of March 2nd bottom table). As one can see, the seasonal precipitation deficit is still under 50% of normal for this time of the year.

So how has this storm impacted the drought in California? There is no question this event was a game changer for the southern portion of California, especially the Los Angeles Area. The wild fire threat has at last been eliminated for the time being and local reservoirs have been partially refreshed, let alone the greening of the previously brown and dusty landscape. Unfortunately, the storm was not a big snow producer in the Sierra (from which the state receives one-third of its water supply). Also, rainfall in northern California was not particularly impressive, and that is where the state’s big reservoirs are located. In fact, comparing reservoir levels between February 25th and March 2nd, we can see little has changed:





Comparison of California reservoir levels pre-storm (top) and post-storm (bottom). Maps from California Department of Water Resources.

The good news is that a series of wet storms are forecast to hit central and northern California this week beginning today (Monday). Very heavy rain amounts are possible in the far north of the state.






One of the Coldest Winters on Record for the Upper Midwest



A map of average temperature departures from normal for the winter of 2013-2014 in the Upper Midwest Region. MRCC graphic.

As everyone knows, it has been bitterly cold and snowy for much of the Upper Midwest this winter. In fact, for several locations it was the coldest climatological (December-February) winter on record. Here is a list of cities that endured their ‘Top 10 Coldest on Record’ winter. All of these sites have POR’s (period of records) of at least 100 years or longer:



March is starting off as the coldest first such week on record since at least 1962. Green Bay, Wisconsin hit -24° this morning (March 3rd), its 2nd coldest March temperature on record (POR since 1886). Flint, Michigan hit -16°, its coldest March temperature on record (previous record was -12°) however the POR for Flint only goes back to 1921. Billings, Montana reached -21° on Sunday morning (March 2nd), its coldest March temperature on record (previous March record was -19° on March 6 and 7 in 1951 (this is a bit suspicious however, and probably based on just the current site rather than the entire historical record. Many coldest so-late-in-season temperature records have also been set and more are likely to occur elsewhere on Tuesday morning this week.

Christopher C. Burt
Weather Historian