ForWarn II

Satellite-Based Change Recognition and Tracking

Hail pellets a city watershed


More information about this event

Disturbance Type(s): Weather

The spring of 2012 was exceptional across much of the eastern US because it occurred weeks earlier than normal. Yet some forests also experienced strong spring hail storms that left leaves in tatters and set spring growth back. Forwarn successfully captured this localized hail event that struck the watershed that the City of Asheville uses as their primary water supply in early May. At the time, some was observed from lower elevation vantage points, but the remoteness of this area affected made it difficult to systematically monitor from the ground. ForWarn captures disturbances like this regardless of their accessibility.

Hail intensity varied over short distances as is shown here and this pattern of variation was confirmed in the field. Areas in red were nearly completely defoliated while just a short distance away leaves were only perforated by hail. By June 14, new leaves were already emerging to replace those damaged by the event. This highlight illustrates how ForWarn can detect ephemeral disturbances that last only a few weeks and how this monitoring system functions successfully during an unusually early spring.