It's been a stormy year for U.S. property insurers, and hurricane season hasn't even started yet.
The shares of insurance companies lately have reflected anticipation of higher premiums but analysts and insurers say there have only been modest premium increases, if any, because companies have so far reserved adequately for disasters, or losses have been lower than expected.
However, that can quickly change.
According to National Weather Service data, there are, on average, 1,200 tornadoes in the U.S. every year. This year there have been 1,076, with 875 in April alone. The cost of covering tornadoes rose, too. According to the Insurance Information Institute, from 1990-2009 the insured costs were $97.8 billion, with $30 billion between 2008 and 2010.