Aerial sketch-mapping of the 1998 ice storm in eastern Ontario

The 1998 ice storm in eastern Ontario was quantified using aerial mapping to determine the geographic area affected, and the severity of damage to the forests. Prior to mapping a reconnaissance flight was used to establish methodology. Mapping was accomplished by experienced technicians flying in a helicopter, 60-100 m above the canopy. Damage was sketch-mapped onto topographic maps then digitized using a geographical information system. Remotely sensed ground cover data were used to remove non-forested and sparsely forested areas from map polygons, to better estimate the area of affected hardwood forests. Damage to conifers was sporadic and occurred as small pockets of 1-5 ha. These were mapped as point data. Comparisons to ground plot measurements made in the spring showed the aerial mapping to be accurate.