This has been one of Maine’s weirdest winter seasons in recent memory, maybe even in a very long time. After several inside runner storm tracks that left the coastline battered and bruised, record warm temperatures, and a snow drought, one would think Mother Nature was done with her surprises.

Nope.

On the last weekend of winter, hail covered lawns around Midcoast Maine as thunderstorms moved through Sunday afternoon. Meanwhile, it was snowing in The County, while southern Maine made a run for 60 degrees.

But was it hail that covered some Mainers’ lawns – or was it really graupel? Let’s discuss.

The American Meteorological Society definition of graupel reads: Heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except for the size convention that hail must have a diameter greater than 5 mm. Sometimes distinguished by shape into conical, hexagonal, and lump (irregular) graupel.

The American Meteorological Society definition of hail reads: Precipitation in the form of balls or irregular lumps of ice, always produced by convective clouds, nearly always cumulonimbus.

An individual unit of hail is called a hailstone.

By convention, hail has a diameter of 5 mm or more, while smaller particles of similar origin (formerly called small hail) may be classed as either ice pellets or snow pellets. Thunderstorms that are characterized by strong updrafts, large liquid water contents, large cloud-drop sizes and great vertical height are favorable to hail formation.

Both pictures above are from hail as a cluster of thunderstorms moved through the Midcoast on Sunday afternoon. You can tell it’s hail and not graupel because of the glassy, opaque surface of the hailstones. If it was graupel, the radar reflectivity would be lighter, and the pictures would show more of a flakey and soft consistency.

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