Summer convection and lightning over the Mackenzie river basin and their Impacts during 1994 and 1995

Abstract

Lightning activity over the Mackenzie basin has been examined for the summers of 1994 and 1995. In recent years, the lightning network operating in the Northwest Territories has detected an average of 118 K strikes per season. Positive lightning strikes (defined as lightning discharges lowering positive charge to the earth) typically comprise 12% of the total. The lightning activity during 1994 was approximately 20% below normal, while in 1995, it was 53% below normal. However, the fraction of positive lightning strikes was 25.6% during 1995. The lightning was linked to synoptic conditions favouring severe storm development, especially those tied to the diurnal cycle. As a consequence of the lightning, as well as the very dry surface conditions, record forest areas were burned. In the Northwest Territories alone, forest fires burned 3 Mha in 1994 and 2.8 Mha in 1995.