Extreme Weather

This year has been another record-breaker when it comes to extreme weather events. Along with late 2010, it was a La Nina year, in which cooler oceanic surface temperatures led to shifts in the jet stream and weather patterns. In the U.S., this normally causes wetter than normal conditions for the East Coast and Midwest, and drier ones in the Southeast. Some of the weather we had was to be expected, but the extent to which it unfolded ended up being historical on many fronts.

In 2011, the United States had the most extreme tornado season of all time, one of the worst droughts since the dust bowl days, severe flooding, record-shattering heat, and several tough storms that hit the East Coast. Consequences of this year’s heat and drought were seen in what also became one of the worst years on record for wildfire outbreaks.

By November, there were a record-breaking 14 weather disasters that cost over a billion dollars each in damage. This was already five more than the previous record, held by 2008.  The most expensive disaster this year was the super tornado outbreak of late April, racking up $9 billion in damages and claiming 321 lives — the deadliest tornado outbreak in recorded U.S. history (figures from the Weather Underground and NOAA).

Climate change debate
Given the expected weather pattern shifts due to La Nina, is there cause to bring climate change into the extreme weather debate? The Intergovernmental Panel for Climate Change (IPCC) believes so. The Nobel prize winning group released a report on November 18 focusing on extreme weather events, linking their increase in frequency to climate change.

What science tells us is that over the past 40 years, oceanic temperatures have risen by 1 degree Fahrenheit, which is enough to start a chain reaction. Warmer water evaporates more quickly, and when combined with warm air and the extra energy it retains, potential for extreme weather increases. Though climate scientists cannot pin specific events on climate change, the trend of increasingly severe weather and severe rainfall over the years has been linked to human influence, and could continue to get worse in coming years.

A positive step to take for the planet’s future would be to pursue more preventive measures to deal with such inevitable disasters once they come our way, to lessen the blow. This includes rethinking our engineering to rebuild flood plains to allow waters to expand, and modernizing and strengthening our infrastructure (dams, levees, roads, bridges). At the very least, we ourselves can make the effort to be more prepared on a personal level.

Global events
In 2011, the U.S. was not alone in extreme weather events. There was drought in Africa, deadly floods during Thailand’s monsoon season, and historically severe floods in Colombia. Queensland, Australia, also experienced floods, its most expensive disaster on record. This harsh weather, coupled with the massive earthquakes in Japan and Turkey, as well as the destructive tsunami, gave Planet Earth (and its inhabitants) quite a thrashing.

The following is a look at the weather that hit us hardest in the U.S., starting with New Year blizzards.

Becky Uline is an editor and musician living in San Francisco, where she enjoys digging into Yahoo! data as a sidekick to trend-finding sleuth Vera H-C Chan. Most of her writing is of the musical variety for her band, the Northerlies.