Plowable Hail Piles Up in Western Nevada

Tom Moore
Published: May 6,2016

Thunderstorms brought accumulating hail to western Nevada.
(Lyon County Manager Jeff Page)

Western Nevada is known for some unusual happenings but Mother Nature provided them with a big one Thursday. Thunderstorms developed near Carson City Thursday, producing hail that accumulated quickly on the roadways.
Unlike severe thunderstorms that develop when temperatures are high and cloud tops reach 50 to 60 thousand feet, this was a colder environment (the surface temperature was around 50 degrees) and cloud tops were much lower.
Because of this hailstones that develop are small and don't usually cause much damage. In this case it was the quantity of hail that created problems.
Hail accumulated quickly and measured at least three inches in some areas. Snowplows were summoned in Lyon County to clear some of the roadways.

While hail in the Reno-Sparks metro area was dime-size or smaller, hail up to half-dollar size (1.25 inches) was reported in Yuba City, California.
(MORE: Large Hail's Underrated Danger)
Also, a funnel cloud was sighted just east of Virginia City, Nevada, and a meteorologist at Naval Air Station Fallon, in western Nevada, recorded a downburst, or a sudden blast of thunderstorm winds, with a peak wind gust to 60 mph Thursday.

Setup For Hail

Atmospheric conditions were just right for hail development over western Nevada.

This map of upper-level jet stream winds from the European (ECMWF) model Thursday shows the deep, southward plunge of the jet stream (trough) near the California coast.

A cold upper trough of low pressure aloft nudged toward the California Coast on Thursday. This situation is a bit unusual for this time of year as ample moisture accompanied the trough.
At the leading edge of the trough, a strong jet stream came screaming northward into Nevada.
The atmosphere was unstable with cold air aloft and the presence of the jet stream provided additional "lift" in the atmosphere, increasing instability and favoring cumulus clouds to further develop into thunderstorms, as opposed to just "fair-weather cumulus".
As moisture rode into the area, these atmospheric features allowed the moisture laden air to rise quickly above the freezing level and hail formed. Because of the extreme situation the hail formed quickly and it literally came down in buckets over a short period of time.

MORE: Layers Inside Hailstones