The hail in this photo appears to be
pea size to about 1/2" in diameter, with a few larger hailstones up to
the size of pennies (the threshold for severe). The hail is
covering the ground, which can happen when a thunderstorm
updraftis very strong, or the storm motion is slow. Often when hail covers
the ground, it cools the moist air above the surface and forms
advection fog as seen here. This fog can be dense, and can combine with
hail-covered roads to cause hazardous driving conditions.