Big Weather Headlines of 2017

A Cold Finish to 2017 for the Eastern United States

It’s a good time to reflect upon some of the many weather headlines across the United States as 2017 comes to a close.  A variety of extreme and/or destructive weather occurred nationwide this year, ranging from a record-setting hurricane season to floods and fires on the West Coast.

Even though final damage figures aren’t available yet, the 2017 Atlantic hurricane season has already become the costliest on record.  For the first time, three Category 4 hurricanes (Harvey, Irma and Maria) made landfall in the United States or its territories.  In August, Harvey became the first major hurricane (Category 3/+) to make landfall in the United States since Wilma in October 2005.  Meanwhile, Irma and Maria both reached Category 5 intensity, but weakened prior to making landfall.  This year was one of only six seasons to feature two Category 5 hurricanes in the Atlantic Ocean Basin.

2017 began with California’s most significant rainfall in several years, which helped bring an end to a multi-year drought.  However, following years of drought and multiple wildfires, the ground was ill-equipped to absorb much of the rainfall.  That led to widespread flooding and mudslides, especially in the burn areas.  Most of central and southern California saw a significant reduction in area of drought condition between January 3 and March 7.

Central and northern California also experienced devastating wildfires in October that affected parts of Napa Valley.  Some vineyards not only lost their crop in the fields, but winery facilities were damaged or destroyed in some cases.  Many of these fires were caused by lightning or downed power lines and spread rapidly due to gusty winds and dry conditions.  The LA Metro Area had major wildfires in November and December, some of which are ongoing.  Parts of southern California are experiencing moderate drought conditions according to the latest Drought Monitor Index.

There were several severe weather outbreaks during the course of the year.  A total of 112 tornadoes developed in the Southeast from January 20 – 22 that caused 27 fatalities.  Meanwhile, another 94 tornadoes developed from February 28 – March 1 from the central U.S. to the Great Lakes Region and south to the Tennessee Valley; and six lives were lost.  NOAA defines a severe thunderstorm as containing any of the following: wind gusts of 58/+ mph, hail 1”/+ in diameter, or a tornado.  It’s possible for a severe thunderstorm to contain one of more of the said criteria.  Colorado’s costliest hailstorm on record occurred on May 8, when the Denver Metro Area saw widespread hail 2” in diameter that damaged cars, buildings and property.

It doesn’t take violent weather like flooding or severe thunderstorms to cause damage.  There was a damaging frost and freeze event from March 14 – March 16 from Tennessee to north Florida.  That event had huge impacts on agriculture in the affected areas.  Locally, the DC Metro Region is concluding its second consecutive drier than average year with a rainfall deficit of more than 14” dating back to August 1, 2015.