The lack of severe weather this year has not only been a local phenomenon, but a national trend as well. The cool pattern that much of the north central and eastern part of the United States has experienced lately has inhibited the severe storm threat for much of the summer season.
This would be one attributing factor to a very positive statistic in which there has been no tornado fatalities since May 13th in the United States. Only one time since 1950 have there been no deaths associated with a tornado in the June through August timeframe in the country. But even with lower tornado numbers this year, around 500 tornadoes were reported since June in the lower 48 states (although most were rated EF0 and EF1). So another aspect to the low death rate this summer can probably be credited to better severe weather warnings and people understanding and taking appropriate shelter during the storms.