2001-2002 California Rainfall Season in Review

The 2001-2002 rainfall season (July 1 to June 30) will go into the record books as one of great contrasts. Totals ranged from near to slightly above normal in the northern thrid of the state, fading to less than half of normal in central California and only a third or less of normal south of the Tehachapis.

Of special note are Los Angeles and San Diego which had their driest seasons on record. The total of 4.42 inches at Los Angeles broke the record of 4.85 inches set in the 1960-1961 season while San Diego had just 3.02 inches to break their 1960-1961 record of 3.46 inches. (Rainfall records in San Diego began in 1851 and in Los Angeles they began in 1872). Both of these rank as at least a 1000-year dry event, or one that would have a probability of occurrence in any given year of 0.1 percent!

The very important 8 Station Northern Sierra Precipitation Index (8SPI) is at about 92% of normal while the runoff has been about 80% of normal. Last year the 8SPI was about 66% of normal and last year's runoff was just 45% of normal.

Distribution of 2001-2002 California Rainfall

Click to Enlarge

2001-2002 Seasonal Rainfall

	Jul	Aug	Sep	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Total	POSN
Eureka	0.20	0.21	0.28	1.00	7.71	11.56	6.37	5.76	4.32	2.42	0.55	0.27	40.65	107%
Redding	0.00	0.00	0.49	0.83	7.38	9.31	3.37	2.82	2.59	1.40	0.68	0.00	28.87	86%
Sacramento	0.00	0.00	0.50	0.36	2.43	6.27	2.19	1.13	2.87	0.11	2.07	0.00	17.93	100%
Santa Rosa	0.00	0.00	0.13	0.96	9.00	11.49	5.02	1.84	2.43	0.64	1.13	0.00	32.64	96%
SF Downtown	0.01	0.05	0.18	0.50	5.18	10.75	2.13	2.59	2.27	0.52	0.84	0.01	25.03	112%
SF Airport	0.00	0.00	0.11	0.31	4.51	8.54	1.38	1.53	2.14	0.38	0.48	0.00	19.36	96%
San Jose	0.00	0.00	0.13	0.12	2.12	4.41	0.75	0.81	1.80	0.35	0.68	0.00	11.17	74%
Fresno	0.08	0.00	0.00	0.29	1.99	1.93	0.76	0.41	0.95	0.21	0.38	0.02	7.02	63%
Los Angeles	0.00	0.00	0.00	0.06	1.42	1.38	0.80	0.29	0.32	0.09	0.05	0.01	4.42	29%
San Diego	0.00	0.00	0.00	0.00	0.99	0.45	0.32	0.17	0.46	0.63	0.00	0.00	3.02	28%

POSN= Percent of Season Normal

2001-2002 California Rainfall Season in Review
by Jan Null, CCM