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Katrina Results in Unprecedented Tornado Events

Hurricane Katrina caused an unprecedented quantity of tornado and pre-tornado circulation weather events. The figure at right shows the Doppler circulation events recorded by the Slidell, Louisiana and Mobile, Alabama Doppler radar sites. One attorney calls this the "measles" map because it has so many "spots" on it.

Some weather experts have opined that the large number of circulation events is due in large part by the dual eye-walls of Hurricane Katrina. These two Doppler radar sites recorded 95 tornado signatures and 4,046 pre-tornado circulation events during Hurricane Katrina.

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Floods - When, Not If

USGS has recently begun publishing some amazing geographic visualizations that illustrate their prowess as 'the' top geo entity in the world. One of these is WaterWatch (http://watch.usgs.gov/waterwatch/). The figure shows a static capture of USGS' map of the real-time streamflow compared to historical streamflow for the day of the year.

Blue and black dots indicate 75 to more than 90% above normal. Large areas above normal mean flooding.

What's the most common and most costly natural disasters in the U.S.?

It's not earthquakes, fires, tornadoes or hurricanes. It's flooding.

Most people think they'll never see a 500-year flood and that if their home has never flooded before, they probably won't ever see a 100-year flood. If you agree with most, you are very mistaken.

Weather and flood experts refer to a flood with a 1% chance of occurrence during a year as a 100-year flood (flood with 0.2% chance of occurrence in a single year was called a 500-year flood).

That gives the wrong impression. It would be no surprise at all if a 500-year flood occurred two years in a row. In fact, if your home is within a 100-year flood zone, there's a 26% chance it'll be flooded over the course of a 30-year mortgage period.

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25% of Bridges Unsafe

The U.S. Federal Highway Administration says that 152,316 of the nation's 599,766 bridges are unsafe! You might think you have 3 in 4 odds of safely crossing a bridge, but you'd be wrong! In six states, more than 40% of the bridges are unsafe. In 42 states, more than 20% are unsafe.

Crossing any bridges today?

Even with fuel prices at astronomical levels, we continue to drive and most cross one or more unsafe bridge twice a day. Wouldn't you like to know where the unsafe bridges are in your area?

In Virginia, Interstates 81 and 95 are heavily traveled by thousands each morning and afternoon. More than half a dozen bridges on each of these critical interstates have been deemed structurally deficient by the Federal Highway Administration.

The news isn't all bad. In 1990, the nation had 238,220 of 572,205 deficient bridges (an amazing 42%). The 2007 data shows 153,316 of 599,766 are deficient (25%).