UPDATED: Hard freeze warning issued for Washington County; protect outdoor vegetation from frost damage

Stock image | Photo by Film Foto/iStock/Getty Images Plus, St. George News

ST. GEORGE — The National Weather Service in Salt Lake City has issued a hard freeze warning for Washington County. The warning is in effect from late Tuesday night until Thursday morning and has the potential to destroy outdoor vegetation, especially in fruit-growing areas like orchards.

Affected area

The warning specifically includes Utah’s Dixie, Zion National Park and St. George.


Update 3:30 p.m. The National Weather Service has extended the freeze warning into northeastern Clark County, including Mesquite, Overton and Moapa. Sub-freezing temperatures as low as 29 degrees are expected in the area.


Timing

A dry airmass, light winds and clearing skies will result in critical temperatures of 26-29 degrees in the normally colder fruit-growing areas through the early morning hours. Frost and freeze conditions could kill crops and other sensitive vegetation and could possibly damage unprotected outdoor plumbing.

Impacts

The main impacts will be in the fruit-growing areas, especially in orchards that are prone to cold temperatures. Any sensitive outdoor vegetation should either be covered or brought indoors for protection from the cold.

Precautionary actions

Shaded areas denote regions subject to the hard freeze warning. Map generated at 8:06 a.m., MDT, Oct. 28, 2019 | Image courtesy of the National Weather Service, St. George News

The Farmer’s Almanac recommends the following to prepare for freezing conditions:

If a frost is predicted, cover your plants. This will both retain as much soil heat and moisture as possible and protect plants from strong winds, which can hasten drying and cooling. You can use newspapers, baskets, tarps, straw and other materials to cover your plants. Cover the whole plant before sunset to trap any remaining heat. Be sure to anchor lightweight coverings to prevent them from blowing away.

Keep the soil moist by watering all plants the day a frost is predicted. Commercial fruit and vegetable growers leave sprinklers on all night to cover plants with water. As the water freezes, it releases heat which protects the plants, even though they’re covered by ice. To prevent damage, the sprinklers need to run continuously as long as temperatures remain below freezing.

Wind also influences frost, and if the air is still and windless, the coldest air settles to the ground. The temperature at plant level may be freezing, even though at eye level, it is not. That can change with a gentle breeze; however, which can prevent the cold air from settling and keep temperatures higher and protects plants. But if the wind itself is below freezing, it can be very damaging instead.

Copyright St. George News, SaintGeorgeUtah.com LLC, 2019, all rights reserved.

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