When it rains, will it hail?

The sound of rain tapping at my roof and windows is very soothing to me. Outside of my family, the one thing I miss about living on the East Coast: a good, soaking rain.  I love and miss that sound so much I sleep to a rain shower app every night.  However, the rains back East rarely created hail.  Since migrating to Colorado in 2006, I’ve had to replace my roof and paint my house twice within an 18-month time span.  After the second roof, I resolved that this is the one sacrifice I must make for the privilege of living in this beautiful state.  I know hail is ice that forms during severe storms, but how and why do some storms produce pea-sized hail and others, baseball sized?

Hail is precipitation which forms into ice balls during severe weather disturbances. Ok, but how? The hail recipe calls for wind, water, freezing temperatures and the ever so crucial “starter” particle, such as a speck of dust. According to hail expert Andrew Heymsfield, pure water can stay in liquid form at temperatures as low at -40 degrees, but something like a dust particle creates a change in the water structure that causes it to freeze. The size of the hail stones is determined by the speed of the updrafts during these storms.  

The stronger the wind speeds the longer the ice participles remain in the air. As these ice particles get tossed around in the atmosphere, they collide with moisture and voila: new layers of ice are formed like an onion.  Once the hail stones become too heavy for the winds to keep them aloft, they plummet to the earth.  Per NOAA, dime-sized hail stones are usually formed during wind speed clocking at 37mph, golf ball size hail stones are formed at wind speeds of 56mph and baseball size hail stones occur when wind speeds reach 100mph.  While rare, in 2010 a small town in South Dakota reported hail stones as large as volleyballs, weighing in at 2lbs.  Storms that produce these gargantuan hailstones are associated with a supercell forming a tornado.   

Will a Colorado thunderstorm take away my love for summer rains and splashing in the puddles under a rainbow in their aftermath? “Hail” No!  Understanding the amazing science behind these little balls of mayhem makes me appreciate the power of Mother Nature even more.