Freezing temperatures ruined an undetermined amount of citrus in Delano early Thursday as a near-record cold settled over the southern Central Valley.
A supervisor of Kern County's Fruit and Vegetables Standardization Program said inspectors found ice crystals in navel oranges.
"That block will mostly likely be out for the season," said the supervisor, Jennifer Stilwill. She added that inspectors will check again in three days to better assess the damage.
There were no early reports of damage elsewhere in the county, though agricultural officials are aware of temperatures as low as 26 degrees for a brief period, and 28 degrees for longer durations.
Temperatures below 29 degrees can destroy some kinds of citrus fruit, depending how long the cold lasts. Freezes rupture juice sacks inside oranges, lemons and mandarins, drying them out and rendering them worthless.
Growers were planning to employ irrigation, wind machines and even helicopters in an effort to circulate warm air throughout the Central Valley.
The National Weather Service reported overnight lows of 29 degrees in Bakersfield and, 19 in the Kern County mountains, just east of Lake Isabella. Bakersfield's record low for the day is 23 degrees.
On the valley floor, the mercury dropped to the mid and upper 20s, meteorologist Brian Ochs at the NWS' Hanford office said. He said the Fresno area got as cold as 29 degrees -- one degree shy of a record.
Similarly chilly weather is expected Thursday night into Friday morning.