CLIMATE OF WNC: TRENDS & HISTORY Jake Crouch October 13, 2014 NOAA’S NATIONAL CLIMATIC DATA CENTER

This Topic’s Goals ▪ Address: Major climate episodes in modern US history, their drivers and their impacts Major climate episodes in WNC history, their drivers and their impacts Historic and recent trends for major climate variables for WNC and what this might mean for those dependent on climate

Modern U.S. Climate History What has happened since the late 1800s (the instrumental record).

Global + US Temperature since 1900 Global and U.S. Temperature Trace

US Temperature Change since 1990

Major Drought Events in US History 1930s: series of drought expansions emanating from Central Plains (the “Dust Bowl”) Mid-1950s: long-lasting drought in much of the Southern, Central and Southeast U.S. In many places, this is the drought of record 2000s: drought pervasive in West, with several major expansions. Also very active in southeast : drought peaks 2012 in Plains and Central Rockies, migrates west in subsequent years : Midwest drought hard on agriculture 1960s were modern historic drought for much of the Northeast

US Climate Divisions

North Carolina Climate Divisions

WNC Temperature since 1895

Temperature Change in North Carolina

WNC Precipitation since 1895

Yes, the Mountains make it difficult Downtown Asheville 37.3” Lake Toxaway 91.7”

Some Fairly Unique WNC Hazards ▪ Tornadoes: very little threat relative to the rest of the South 6 tornadoes; 4 tornado-days since 1950 ▪ Elevation and terrain plays havoc with winter precipitation type Toughest forecast in the business ▪ Floods and Drought are important hazards

Major Flooding in WNC ▪ Spring to late-spring is usually high- flow time for WNCs rivers ▪ Any major rainfall event can generate flooding on small streams ▪ Any major rainfall episode can generate flooding on rivers ▪ Landfallen tropical storms can generate very large and flood producing rains (in addition to wind damage) ▪ Hurricanes Frances, Ivan and Jeanne contributed to epic, catastrophic flooding in 2004 ▪ Frances track approaches a worst- case scenario for WNC

Major Drought Events in WNC History Mid-1920s Late 1980s 2000s: Lake Hartwell drops significantly

“Northwest Flow” snow events Lower-level winds are from the northwest Orientation of mountain ranges (and Appalachians as a whole) can enhance uplift needed to create precipitation (snow) Particularly along the N and W faces Even a pedestrian storm system can make lots of snow if the winds and moisture are lined up right Higher elevations can see outsized impacts in NW flow events Asheville Boone

Climate Change in North Carolina

Summary

Great Resources ▪ NC State Climate Office Overview: climate.ncsu.edu/climate/ncclimate.html climate.ncsu.edu/climate/ncclimate.html ▪ Climate at a Glance (US):

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