Tornado season in the USA is in full swing

A series of 25 storms hit a wide area from Oklahoma to North Carolina last weekend and left over 45 people dead and extensive damage, also forcing the shutdown of two nuclear reactors. They were only some of the 1000-1200 tornadoes that hit the USA every year with more than 55% of them from April to June. 2003 was an exception when 1,376 tornadoes were reported, the highest number in one year and meteorologists worry that 2011 could witness the same situation.

Since 2007, the intensity of the tornadoes in the USA is measured using the Enhanced Fujita Tornado Damage Scale. In fact, the inventor of this scale, Dr. Tetsuya Theodore Fujita, designed a system that only estimates the wind speeds based on the damages left behind by tornadoes. The strongest tornado last weekend was rated EF3, which means it had 136-165 mph winds.

These tornadoes reignited debates about requirements to make buildings more hurricane resistant.

According to engineers, homes in the USA can stand from 90 – up to a maximum of 110 mph winds. Tornadoes incurred on average 50% of all U.S. insured losses and everybody would be interested to find a way of reducing them. The problem is that even an EF1 rated tornado generally determine extensive damage to any building. EF2 and EF3 tornadoes practically give no chance to a house. Nevertheless, some things can be done. Using two-pane windows and strengthening garage doors (a weak spot in a home) in case of high winds helps you avoid internal pressurization that usually make walls and ceilings burst. Replacing poor shingles with high quality ones prevents their rip off when hurricanes start and avoids greater damages.

U.S. homes are designed to last 50 years and the probability to be hit by a hurricane in that time is extremely low if situated in an area with an average risk. Buildings in Texas, Oklahoma, Kansas, and Nebraska, an area known as “Tornado Alley” are at a greater risk and the solution is building special tornado-resistant shelters in house or underground. Average prices for such shelters are USD 5,000. Building homes stronger is not an option, because only making them 10 times more resistant could give some positive results and this would sharply increase building costs.