How Much U.S. Summers Have Warmed Since 1970

June is here and one summer statistic has already emerged; the season has been getting hotter across the U.S. since 1970.

Nationwide, the summer warming trend averages out to a little more than 0.4°F per decade since 1970. The places warming the fastest also happen to be some of the hottest places in the country, with a large chunk of the Southwest and all of Texas warming more than 1°F per decade.

Of the 344 climate divisions, which are set by the National Climatic Data Center and divide the country into climatically-similar zones, less than 10 percent have seen a summer cooling trend. In general, every state in the lower 48 has warmed since 1970 and the most recent decade was the warmest on record for the country.

Those trends are consistent with the overall warming that has been observed for the planet as greenhouse gases emitted by humans build up in the atmosphere.

For this summer, the Climate Prediction Center (CPC) is forecasting a large "U" of areas where above normal temperatures are more likely running from down the West Coast across the South and back up the Eastern Seaboard.

CPC also forecasts below normal temperatures are likely in the Upper Midwest based overarching climate conditions. While El Niño is likely to form this summer, its impacts on weather patterns in the U.S. won't generally become pronounced until fall.

What’s In A Hurricane’s Name?

Would more residents of New Orleans have evacuated ahead of Hurricane Katrina in 2005 if it had been named Kurt?  A published study suggests they would have, perhaps reducing Katrina's death toll of more than 1,800.

Because people unconsciously think a storm with a female name is less dangerous than one with a masculine name, those in its path are less likely to flee, and are therefore more vulnerable to harm.  As a result, strong Atlantic hurricanes with the most feminine names caused an estimated five times more deaths than those with the most masculine names, researchers at the University of Illinois at Urbana-Champaign wrote in Proceedings of the National Academy of Sciences.

When the National Hurricane Center began giving storms human names in 1953 with Alice, it used only women's. The first "male" Atlantic hurricane was Bob, in 1979.  Hurricane names currently alternate between male and female. Among those the World Meteorological Organization has chosen for 2014: Dolly, Josephine, and Vicky.

Based on the analysis of Atlantic hurricanes from 1950 to 2012, when 94 made landfall, the researchers found that names of less severe storms didn't matter. Whether people took precautions or not, the death toll was minimal and no different for male and female names.  But for strong hurricanes, the more feminine the name - as ranked by volunteers on an 11-point scale - the more people it killed.

When judging a storm's threat, people "appear to be applying their beliefs about how men and women behave," said co-author Sharon Shavitt, a professor of marketing at Illinois. "This makes a female-named hurricane, especially one with a very feminine name such as Belle or Cindy, seem gentler and less violent."

A spokesman for the National Hurricane Center declined to say whether scientists there find this analysis credible. But "whether the name is Sam or Samantha," Dennis Feltgen said, people must heed evacuation orders.

What Causes Hurricanes?

Thanks to big storms such as Hugo and Katrina, hurricanes are household names, known for sweeping in death and destruction on winds capable of topping 150 mph. But unlike tornadoes, which strike quickly and with little notice, hurricanes usually takes days to form.

 The huge, swirling storms start as tropical disturbances, when rain clouds build over warm ocean waters, generating wind speeds less than 38 mph. If the winds of the rotating storm are from 39 mph to 73 mph, it's labeled a tropical depression; at 74 mph, it officially becomes a hurricane.

A hurricane's strength is based on its wind speed and ranked using the Saffir-Simpson Hurricane Scale. A Category 1 storm is dangerous, but a Category 5 storm is likely catastrophic, bringing winds faster than 157 mph. Hurricanes Hugo in 1989 and Katrina in 2005 were Category 5 storms. Though the high winds can be treacherous, the greatest threat during a typical hurricane is the storm surge, a wall of water that can be 100 miles wide and 15 feet deep and covers the coastline when a hurricane lands.

5 Quick Facts About Hurricanes

• The difference between a hurricane and a typhoon is simply where it happens. Both are tropical cyclones, called hurricanes in the Atlantic Ocean, Caribbean, and eastern Pacific Ocean, and referred to as typhoons west of the international date line in the Pacific Ocean.
• Names are given to tropical storms (which may or may not develop into a hurricane) in alphabetical order, alternating male and female names, and skipping names that start with the letters Q, U, X, Y and Z.
• It's a common myth that opening a window during a hurricane will help equalize the pressure in your home, but the reality is that doing so will only invite in more wind and debris.
• The deadliest tropical cyclone in history was Bangladesh's Great Bhola Cyclone in November 1970, which killed as many as 500,000 people.
• Superstorm Sandy, while destructive, was downgraded from hurricane status. Officially, it was Post Tropical Cyclone Sandy, but the superstorm name given by media outlets stuck.