The National Weather Service issued a frost watch at 3 a.m. Thursday, effective from 11 p.m. until 9 a.m. Friday for the foothills of Northern Oregon’s Blue Mountains.

The weather service describes: “Subzero temperatures as low as 28 degrees possible.”

“Freezing and freezing conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing,” the weather service says. “Take steps now to protect tender plants from the cold.”

What to do if there is a frost watch or warning

Frost warnings are issued from May to October (but can be extended if necessary), when low temperatures are expected to be between 29 and 32 degrees. If there is a risk of temperatures falling below these thresholds, a frost watch may be issued a few days in advance.

According to the weather service, if a frost warning or watch is issued for your area, there is little you can do to protect the plants. If you can move your sensitive plants indoors, do so because freezing temperatures will likely kill them, depending on the severity of the conditions.

Advance Local Weather Alerts is a service provided by United Robots, which uses machine learning to compile the latest data from the National Weather Service.