If a hailstone the size of a football kills your cow and melts in your sink, you have a freezer full of beef and a heck of a story, but you might not officially have a record.
Up until now, the state hasn’t had a comprehensive, defensible manner to prove one giant hailstone is bigger than any other that has previously fallen in the state.
Now, the Colorado Climate Center at Colorado State University has joined with National Weather Service offices that serve Colorado and other meteorologists to instruct the public on how to help.
State climatologist Nolan Doesken, who has been tracking Colorado hail data for more than 30 years, recorded a 4.5-inch stone July 30, 1979, but there are at least 18 similar reports, some better-documented than others.
Scores of Coloradans would argue that they’ve seen larger hail but didn’t bother or know how to try to prove it at the time, he said.
“In many ways, it is the ‘gee-whiz’ factor,” Doesken said. “For me, if I got hit in the head by a 5-inch hailstone, it probably wouldn’t make much difference if it was actually 5½ inches; I’d still be having a very bad day.
“But we should have a structure in place to confirm the size of extreme hailstones. … To know the whole extent of weather extremes in a state like Colorado is valuable information.”
When a big stone falls, time is of the essence, given their nature to melt or evaporate, Doesken said.
First, hailstone collectors should contact the National Weather Service or local law enforcement agencies. That will help forecasters warn others in the area about damaging hail so they can take cover and get animals indoors.
Doesken said that as soon as it’s safe to go outside after a hailstorm, people should retrieve the largest stone. With witnesses, they should use a ruler to measure its diameter and a flexible tape measure or string to record its circumference, and, if possible, weigh the stone.
The stone then should be tightly wrapped with plastic and stored in a freezer in an airtight plastic bag, Doesken said. An unsealed hailstone will still shrink and change.
Those who find hailstones of 4.5 inches in diameter or greater should contact Doesken at 970-491-8545 or nolan@atmos.colostate.edu.
Doesken realized a couple of years ago that Colorado had no good repository of extreme-hail data as he helped verify a that fell in Vivian, S.D., on July 23, 2010.
At about the same time, he helped verify a record in Vermont, as well as set up . When a former student, Jennifer Stark, meteorologist-in-charge of the National Weather Service office in Pueblo, asked about hailstone records, Doesken faced the gap in his data.
“The motivation has been that other states have been establishing these repositories, and Colorado should have done this long ago,” he said. “If you’re going to get hit with something that big, you might as well take some credit for it.”
Joey Bunch: 303-954-1174 or jbunch@denverpost.com
Measuring hailstones
A large stone should be measured for diameter, circumference and weight.
Pingpong ball: 1.5 inches
Golf ball: 1.75 inches
Tennis ball: 2.5 inches
Baseball: 2.75 inches
Hockey puck: 3 inches
Softball: 4 inches
Grapefruit: 4.5 inches
CD/DVD: 4.75 inches
Source: ColoradoClimate Center
