Sonoma County grape growers use technology to battle frost

Call it “Moneyball” for the vineyards.

Just as Oakland A’s general manager Billy Beane used data analysis to find bargain baseball players to put his team into the playoffs, local grape growers now can benefit from similar analytics to help them with frost and heat protection as well as water management.

“It doesn’t care who you are or what you do. If you are better informed, you can make better decisions,” said David Reynolds, senior research meteorologist with the Cooperative Institute for Research in the Environmental Sciences.

The new high-tech tools are taking on added importance as bud break has started earlier than normal this year, exposing the North Coast’s $1.5 billion grape crop to the threat of frost damage. Freezing temperatures already have been reported this week, prompting growers to turn on their wind machines and spray their vineyards with water to prevent the tender buds from freezing.

Growers can receive either email or text alerts calibrated annually to certain weather parameters from 12 automated stations based around Sonoma County, with vineyard managers able to view ?real-time data on their smartphones or computers.

They can receive morning and afternoon frost forecasts with additional information on new topics, such as a powdery mildew index to combat against disease, and historical analysis going back to 2011.

The system is complemented by work done at the National Oceanic and Atmospheric Administration and other government agencies that have installed 15 frost inversion towers in Sonoma and Mendocino counties. Six more will installed by early March, going from Sebastopol to Lake Mendocino.

Those towers measure the height of warm air during frost conditions, known as inversion, at elevations of 35 feet and 5 feet. If the warm air is close enough to the ground, growers can use fans to mix it with the colder air to stave off frost and eliminate the need to use water to provide a protective icy coat over the vines.

“We need to tell them what the delta (difference) is between 35 feet and 5 feet and say, ‘This is good enough. The fans will work today,’?” Reynolds said. Growers can now get such data in real time and be able to check it throughout the night.

The data tools, which play a crucial role for grape growers seeking to conserve water in the midst of a historic drought, were discussed Thursday during a meeting sponsored by the Sonoma County Winegrowers and the USDA Risk Management Agency.

The Kunde Family Estate Winery and Vineyards in Kenwood has a weather monitoring station on its 600 acres, which is one of the colder locations in the county, providing data every 15 minutes.

“We have the forecast and we have the real-time data from the days before so we can verify accuracy,” said Steve Thomas, director of vineyard operations for Kunde. “We use it in the summertime also … anticipating irrigation need and avoiding putting on too much water. There is a disease model also for grapes, which is really nice.”

Sonoma County weather patterns are difficult to track, given its many microclimates, said Matt Wanink, meteorologist for the Western Weather Group, which provides data to growers through the Sonoma County Winegrowers website.

Several days ago, for example, the winds at Kenwood were gusting at 40 mph in the morning at a temperature of 55 degrees, while in Graton the winds were at 2 mph with a chill at 32 degrees. “It can be very difficult, but it is a fun challenge,” Wanink said.

Such services are especially beneficial for growers in the Russian River watershed who must abide with new rules over their diversion of water from the basin after losing a court challenge against the state Water Resources Control Board.

Such analysis also can help government officials tasked with maintaining sufficient water levels at Lake Mendocino, the main reservoir in the upper Russian River basin, Reynolds said.

If they know that a large storm is coming, for instance, the Army Corps of Engineers could release water from Coyote Dam more efficiently over a longer period with assurances that the incoming rainfall is sufficient to replenish the reservoir.

The monitoring also can work in summer, when heat spikes can require growers to water the vines to prevent their grapes from drying out or their growth being slowed.

“Say Sonoma County Water Agency knows a heat wave is coming, people are going to be watering their crops for stress relief. They may release some water, if they have it to release, so there is no dropping of the flows,” Reynolds said. Preventing river levels from dropping averts damage to protected fish during heat spikes.

Reynolds said he would like to expand the weather monitoring system to make it more accurate, especially for rainfall. One way is to use buoys or drones that cast a longer reach into the Pacific Ocean, as current five-day storm projections can be off by as much as much 500 kilometers.

“We need to go way out into the Pacific to get that information,” he said.

The new frost rules also will provide additional insight as growers in the Russian River watershed will have to report when they use water during the spring for frost protection and from what source, allowing scientists to match that reporting with daily temperatures in the different regions to provide a more complete picture of water consumption, Reynolds said.

You can reach Staff Writer Bill Swindell at 521-5223 or bill.swindell@press-?democrat.com. On Twitter ?@BillSwindell.