Frost/Freeze in Grand Valley, Colorado

Minimum temperatures across the zone ranged from 32F to 23F during this event. The lowest recorded temperature of 23F occurred at two sites, AV979 and E8921, both mesonet sites. The KGJT ASOS at the Grand Junction regional airport recorded a minimum temperature of 27F. 15 of the 18 available sites recorded temperatures at or below 32F for at least 3 hours, with an average duration of 6 hours. Only 6 of the 18 sites recorded temperatures at or below 28 degrees for at least 3 hours, with an average duration of 3.5 hours. Based on these data, this event for this zone qualifies only as a Freeze.

An unusually cold air mass had moved in over eastern Utah and western Colorado by the night of April 6th to the 7th. This already cold air was compounded by clear and calm conditions that promoted radiational cooling across much of the region. At this point in the year, only the lowest elevations of eastern Utah and western Colorado had acquired enough Growing Degree Days to warrant freeze highlights, as important agricultural assets, with particular emphasis on fruit trees, were beginning to bloom and a hard freeze event could be disastrous. Luckily, many of these crops were not damaged by this freeze event, even though many locations did hit hard freeze criteria.