Cold in California, December 20 to 27, 1998

On December 19th an arctic airmass began moving over Central California. The resulting cold air pool from advection and radiational cooling in the lowest levels of the atmosphere led to a devastating freeze to crops, especially citrus, in the Central and Southern San Joaquin Valley from December 20th through 27th. Estimates of direct crop loss reached $596M for the Central and Southern San Joaquin Valley with an indirect economic loss estimated at $2.7B to local area economies. The largest percentage of area crop losses were to lemons and oranges but several other unharvested fruit and vegetable crops, including avocados and broccoli, also suffered widespread damage. Mornings of freezing temperatures lasted from the 20th through the 30th but the coldest mornings of concern to agriculture generally ended on the 27th. On the morning of the 23rd, for example, minimum temperatures dropped to the 16-24 deg F. range with time durations less than 28 deg F. in excess of 16 hours in many locations. Fresno had a record low maximum temperature of only 34 deg F. on the 21st eclipsing the old record of 35 deg F. set in 1908. A record low maximum temperature was seen in Bakersfield on the 22nd with the mercury only reaching 34 deg F. and only 35 deg F. for Fresno. Subsequently a record low temperature was tied in Bakersfield on the morning of the 23rd with a 19 deg F. reading. This freeze was eerily reminiscent of a similar event during the same time period in December of 1990.