Gigantic, near record-size hailstones pummel northern Maryland

Jeff Halverson and Jason Samenow
Washington Post
Wed, 24 Jun 2015 15:09 UTC

As a violent thunderstorm tore through northern Maryland Tuesday evening, it unloaded massive hail - large enough to rank among the biggest in Maryland state weather records.

Nicka Pohl shared with Capital Weather Gang the photo of a softball-size, spiked hailstone measuring approximately 4 inches in diameter, which fell near Timonium. Hail larger than golf balls fell throughout the Hunt Valley, Cockeysville, and Timonium areas in northern Baltimore County.

The hail dented cars all over the area and smashed back windows, Pohl said.

Christopher Strong, the warning coordination meteorologist at the National Weather Service forecast office serving Washington and Baltimore area, said Maryland records show there have been only two instances of hail larger than the 4-inch stone Pohl collected. Hail measuring 4.5 inches in diameter was observed in LaPlata in 2002 when a large, violent F4 tornado swept through the area. And a stone measuring 4.5 inches was reported in Baltimore in 1970.

The thunderstorms that produced the hail formed thanks to a very unstable air mass and strong wind shear (increase in winds with altitude) ahead of a cold front approaching from the northwest.

A nearly solid band of thunderstorms, called a squall line, swept through during rush hour (image below).