Whipsaw weather changes up and down the Golden State, including warm spells in January and early February, followed by Central Valley cold snaps in mid to late February, have almond growers and state agriculture officials concerned about freeze damage.

How much damage has been done to California’s lucrative almond crop won’t be known until harvest time comes, August to October. The U.S. Department of Agriculture estimates the 2016 California almond crop was worth $5.16 billion. An estimate for 2017 is not yet available.

California produces about 80 percent of the world’s almonds on close to 1 million acres, from Tehama County to Kern County, Dave Kranz, communications and news division manager for the California Farm Bureau Federation, said Tuesday in a phone interview.

Leading almond-producing counties in the Golden State include Kern, Fresno, Stanislaus, Merced and Madera, which represent more than 70 percent of producing acreage statewide, according to the California Department of Food and Agriculture.

Almond trees typically bloom in mid-February and this year they bloomed at least a few days early due to warmer than normal temperatures in January and early February, Kranz said.

Damaging freeze

Then came the freeze in mid-February to late February. That freeze was far more damaging than the cold storm of early March that brought rain to valley farms and significant snow to the Central Sierra.

“We think the almond crop is probably the most affected by the freeze in mid to late February,” Kranz said. “That’s a concern because the almond trees were in bloom at that time and they were vulnerable to potential damage from the freeze.”

Most other tree crops, including peaches, cherries, plums, and nectarines were dormant during the mid to late February freeze, and so were grapevines, Kranz said.

“As we move forward in to March those fruit trees will begin to bloom and become vulnerable and the grapevines will begin to bloom,” Kranz said.

The mid-February to late February freeze also caused some worry for citrus growers in the south San Joaquin Valley. Some trees were bearing fruit at the time and some were blooming.

“When that freeze hit it was a concern for orange growers down south,” Kranz said. “Some citrus trees were in bloom so there may be some damage but that remains to be seen. They think they came through it ok.”

The cold storm last week was probably more positive than negative for valley farmers because they need the rain and additional snowpack in the midst of a dry winter. Farmers would be concerned about rain and wind, but on the whole they’d prefer to have the rain because it’s been so dry.

“Rain will help and snowpack will take some edge off the dry winter,” Kranz said. “We had hail in some places but it was scattered and we don’t know yet if it did much damage.”

How much damage?

It’s too early to tell how much California’s almond crop has been harmed by the freeze. Growers like Steve Van Duyn, who manages an orchard southeast of Galt, have cut into almond blossoms to determine if the February freeze killed blossoms. He found some dead blossoms and he found others with developing almonds in good health.

“Everybody’s waiting to see,” Kranz said. “Growers recognize there has been damage but exactly the extent of it won’t be known for some months until the crop is harvested. There’s a lot of time between now and then.”

Some growers recently treated their orchards in advance of rain last week, to prevent fungal disease that come with rains.

No one knows if there’s going to be a shortage of almonds this year. Kranz said he can’t imagine there will be a shortage. He says growers produce a lot of almonds and they store a lot of almonds year to year.

“I don’t think there will be a shortage,” Kranz said. “Everybody expects there to be impacts, but I don’t see a shortage.”

Alicia Rockwell, director of corporate communication and public affairs for Blue Diamond Growers, a cooperative of about 3,500 California almond growers, said, “Regarding the crop, it is still too early to know the extent of any damage that may have been caused by the adverse weather past few weeks.”

Field management teams are working closely with grower-owners to support their needs as the crop develops, Rockwell said.

Asked for perspective on the freeze and potential crop damage, Carissa Sauer, industry communication manager for the Almond Board of California, described how vulnerable almond blossoms are key to producing the nuts.

When they are pollinated by honey bees, almond blossoms begin growing into almonds. But if sustained, below-freezing temperatures come during the bloom period or early development stage that follows, each blossom or new almond is at risk of frost damage.

It is too soon to tell how the late February cold snap will impact the coming almond crop, Sauer said.

The threshold between minimal crop damage and total loss is just two degrees, Sauer said.

So almond farmers try to manage freezing nighttime temperatures at bloom by turning on irrigation sprinklers to increase local temperatures; mowing vegetation growing in orchard rows which, if left in place, prevents heat from rising off the ground; and turning on orchard fans or wind machines to mix warmer higher air with cooler air near the ground, and increase the temperature in the orchard canopy.

Sauer said almond growers can also choose orchard locations that are less prone to freezing temperatures, and they can select tree varieties that bloom later and are less likely to encounter frost.

Over the past two decades, the total salable supply of California almonds has increased from 664.4 million pounds in 1998-99 to 2.49 billion pounds in 2016-17 and an estimated 2.6 billion pounds in 2017-18, according to the Almond Board of California, which is based in Modesto.

According to the USDA, the estimated annual value of California’s almond crop fluctuates year to year. In 2012, the estimated value was $4.82 billion, in 2013 it was $6.38 billion, in 2014 it grew to $7.39 billion, in 2015 it fell to $5.87 billion, and in 2016 it came in at $5.16 billion.

Contact Guy McCarthy at gmccarthy@uniondemocrat.com or 588-4585. Follow him on Twitter at @GuyMcCarthy.