A microburst is shorter-lived, but more destructive than a macroburst. It is generally associated with a stationary or slow-moving intense thunderstorm. Flash flooding is a special hazard in mountainous terrain, where excess water runs off to creeks, streams, rivers, or sewers, or collects in other low-lying areas. Because of their design and composition, urban areas are prone to flash floods during intense rainfall. It develops in intense thunderstorm cells characterized by strong updrafts, great vertical development and an abundant supply of supercooled water droplets.
Hailstones range from pea size to the size golfball or even larger.
In general, stronger the updraft, the larger will the ice crystal grow producing larger hailstones. As many as 25 layers have been counted in a single large hailstone. Hailsreak is the accumulation of hail in a long, narrow path along the ground. It forms following hail formation, weakening updraft and hailstones reaching the ground. It takes about 15 to 20 minutes from the formation of hail to the depositing hail at surface.