Having severe weather this time of year is not unusual at all. The amount of it, though, is running way ahead of normal levels.
So far this month, 886 tornadoes have been reported in the United States. Surveys and studies are still being conducted on confirming how many reports were actual tornadoes.
Last April, the number of actual tornadoes was 139 (226 in 2009 and 189 in 2008). The "normal" amount of April tornadoes runs around 185.
The number of reported tornadoes for the year thus far is 1078. For this period, the normal value is around 378. (Again, "reported" tornadoes does not mean officially confirmed--since multiple reports of the same tornado can be included).
So far this year, 45 people have died in 15 tornadoes. This represents the same amount killed in ALL of 2010 in 21 tornadoes.
May, June & July are very active months, with June being the statistical high point of tornado occurrence. So, the severe season has a long way to go.