December 2017 North American winter storm

A winter storm, unofficially named Winter Storm Benji by The Weather Channel and Storm Zubin by the Free University of Berlin, impacted portions of the Southern, Mid-Atlantic, and Northeastern United States, and later across portions of Europe in December 2017. First developing as a low-pressure area in the Gulf of Mexico, the storm system impacted the Southern United States on December 8, producing rare snowfall totals and causing hazardous travel impacts across the South. The low then moved northeastward, reaching the Big Bend and western portions of Florida, while continuing to produce snowfall totals north of the low, across a narrow band stretching from Alabama to North Carolina. A second low-pressure area formed thereafter on December 9, producing additional snow totals across the East Coast of the United States, including portions of the Mid-Atlantic and Northeastern United States, before the low moved inland over Nova Scotia and The Maritimes the day after. After moving offshore, the low-pressure area strengthened, progressing over the northern Atlantic Ocean before moving over Sweden and Finland and subsequently dissipating.

The impacts of the winter storm in the Southern United States set numerous snowfall records across Texas and Louisiana and caused extensive damage to power infastructure and property damage that totaled $965,000, including $820,000 in Mississippi alone. Additionally, snowfall fell in the Florida panhandle, with snow flurries being reported as far south as Miramar Beach, Destin, and Pensacola. In southern Florida, severe weather also occurred after a squall line developed along a cold front, which produced wind damage that caused $50,000 in property damage across western and southern parts of the state. In the Mid-Atlantic and Northeastern United States, hundreds of vehicle accidents occurred from the heavy snowfall and resulted in New York City receiving its first major snowfall of the 2017–18 winter season. The low-pressure area associated with the winter storm also caused high winds across Germany and severe weather in Switzerland. Overall, the impacts from the winter storm killed eight people and injured at least 45 others.

Meteorological synopsis
On December 5, 2017, a cold front moved through southern Texas, bringing rainfall and cold air behind it. The front then intensified, which caused temperatures across the region to further decrease into the 40-50 F range and resulted in the cooling of the atmosphere by December 7. On the same day, a separate cold front progressed across portions of the southern Great Plains and the Southeastern United States. The combination of the atmospheric cooling, cold temperatures, and the cold front resulted in a wintry mix developing across southern Texas on December 7 and 8. As the cold front progressed eastward, a broad area of southwesterly wind above the atmosphere developed in the Gulf of Mexico along an upper-level trough that was located across the southern Plains, as moisture was pulled into the trough. A low-pressure area developed in the Gulf of Mexico along a frontal boundary, and moved northeastward towards the Big Bend region in Florida. A zone of intense frontogenesis also formed north of the low-pressure area near the Texas coast, and moved northeast parallel to the low, producing heavy snowfall across a narrow area extending from east-central Alabama to northern Georgia to western North Carolina.

As the low moved across the Southeastern United States on December 9, another low-pressure area developed along a surface front off the Carolina coast. The second low tracked northward, producing additional snowfall across the Mid-Atlantic and the Northeastern United States, before moving inland across Nova Scotia on December 10. The low-pressure area then reached a pressure of 983 mb while over The Maritimes in the late morning hours of December 10. As it moved northeast and continued to strengthen away from Newfoundland and Labrador on December 11, the low-pressure area traversed the northern Atlantic Ocean before moving inland over Sweden on December 15. It then moved over Finland on December 17 before dissipating on December 18. The winter storm was unofficially named Winter Storm Benji by The Weather Channel and Storm Zubin by Free University of Berlin, and was rated as a Category 2 in the United States with a Regional Snowfall Index of 3.077 by the National Oceanic and Atmospheric Administration.

Texas
Icy conditions led to a 26-car collision on a Interstate 410 ramp near San Antonio on December 8, which injured one person and forced the closure of the ramp. Vehicle accidents also contributed to closures on Interstate 10 and Interstate 610. Numerous highways and roads were covered in ice, including Interstate 10, Interstate 45, and Interstate 69, which created hazardous travel conditions. There were several vehicle crashes across the Houston area. Snow fell across several major cities in the state, including in Austin, Houston, and San Antonio, and snow fell as far south as Brownsville, where a trace of snow fell on December 8, which was the second-ever measurable snowfall there and set a daily snowfall record. In addition, Corpus Christi received measurable snow, the first since 2004, and San Antonio received snowfall in December for the second time on record, which was also the second-earliest snowfall there. Additionally, measurable snow fell in Houston in December for the first time since 2009, and daily snowfall records were broken on December 7 and 8. The Beaumont-Port Arthur area received its first December snowfall ever, where 3 in of snow fell, and was also tied for the second-highest snowfall total ever. In Laredo, 1.7 in of snow accumulated, which set a snowfall record on December 8. Multiple flights were delayed at Austin–Bergstrom International Airport, where 1.3 in of snow fell and the first snowfall in December since 1948, and nearly 63,000 power outages occurred across Texas. Several people contracted hypothermia that resulted from the cold temperatures and low wind chills caused by the winter storm, which killed three people and hospitalized two others. Across the state, the winter weather impacts caused $85,000 in property damage.

Louisiana
As a winter weather advisory was in effect for central portions of Louisiana, Lafayette and Lake Charles recorded their snowiest December days on record, with 2.1 in and 1.7 in of snow respectively. Snow fell across the Baton Rouge area as well, covering vehicles with snow, as 3.5 in of snow fell, which was the third-highest total recorded there. A trace of snow fell in New Orleans, as the state experienced below-freezing temperatures, causing ice to form, and resulted in seven casualties. In Kentwood, 6.5 in of snow fell, the highest snowfall total across the state, while 5 in of snow fell in Catahoula Parish southwest of Jonesville. There were 63 vehicle crashes across St. Helena, St. Tammany, Tangipahoa, and Washington parishes, and nearly 100,000 power outages occurred across the state. Icy conditions on overpasses closed portions of Interstate 10, and a curfew was set in Tangipahoa Parish as there were more than 29,000 power outages across the parish. Several shelters were opened in New Orleans, while a warming shelter was opened in St. Tammany Parish. A motorcycle restriction was implemented on the Lake Pontchartrain Causeway bridge following the winter storm, and in Catahoula Parish, property damage amounted to $10,000.

Mississippi and Alabama
Winter storm warnings were issued for numerous counties in Mississippi as more than 6 in fell across southwestern portions of the state. Numerous school districts across the state were closed in preparation for the winter storm. Jackson received 5.1 in of snow, which was the sixth-highest snowfall total recorded there, while two locations separately in Jones and Lamar counties received 8 in of snow. Additionally, 5 in of snow fell in Meridian, which was recorded as the third-highest snowfall accumulation on record. Across the state, there were nearly 80,000 power outages, and there was $820,000 of property damage.

Across Alabama, the heaviest snow fell across eastern portions of the state, mainly across Clay, Cleburne, and Randolph counties. The heaviest snow in the state fell in Delta, where 15 in was recorded, which was the seventh-highest snowfall in the state's history and the second-highest snowfall in December. In St. Clair County, 6 in of snow fell in Ragland, setting a county record for the highest snowfall accumulation in a day. Prior to the winter storm, more than thirty-six school systems were closed. There were several vehicle accidents on Interstate 65, including one which closed all southbound lanes of Interstate 65 in Shelby County, in Calera. Nearly 45,000 power outages occurred across the state, including nearly 10,000 outages across the Birmingham area. In Mobile, 1 in of snow fell, which was the earliest measurable snow there, while 4 in of snow fell at Birmingham–Shuttlesworth International Airport, which was the third-highest snowfall in December there. As of December 2023, Birmingham has not seen more than 1 in of snowfall.

Georgia
Before the winter storm impacted Georgia, winter storm warnings and advisories were in effect for numerous counties. The heaviest snow fell across northern portions of the state, and the heavy snowfall caused extensive damage to power infrastructure. A seven-vehicle crash closed all lanes of the Langford Parkway in Atlanta on December 8, and numerous schools across the state, including schools across Metro Atlanta, were closed or dismissed early. There were nearly 1,600 flights cancelled and another 930 delayed at Atlanta International Airport, including the cancellation of more than 600 Delta Air Lines flights on December 8. Additionally, there were more than 325,000 power outages across northern Georgia, including more than 30,000 outages across the Atlanta metropolitan area. One person was killed after being electrocuted from a downed power line. During the winter storm, an emergency warming shelter was opened in Atlanta.

North Carolina
In preparation for the winter storm, several businesses, schools, and government offices were closed. The full length of the Blue Ridge Parkway in North Carolina was closed, and North Carolina Highway 128 was also closed. Additionally, Mount Mitchell State Park was closed, and Asheville Mall, along with Asheville Outlets, opened late on December 8. Two state football championship games were delayed; one between Wake Forest High School and Mallard Creek High School, and the other between Scotland High School and Harding University High School. Two events that state governor Roy Cooper was scheduled to appear in were postponed.

The heaviest snow fell across western portions of North Carolina, causing 54 vehicle accidents. The total of vehicle accidents included one which injured two people and briefly closed all eastbound lanes of Interstate 40, while another crash near Sylva that injured one person. Another crash occurred at a shopping center in Burke County, which injured one person, and several crashes occurred on the Triangle Expressway and on Interstate 540. Delays occurred across several highways, including on Interstate 26 and Interstate 40, and the heaviest snow for the winter storm and in the state fell on Mount Mitchell, where 25 in was recorded. Several flights were cancelled at Asheville Regional Airport, and more than 39,000 power outages occurred across North Carolina. A warming center was opened in the Asheville area by the American Red Cross.

Elsewhere
Snow fell as south as the Florida Panhandle, including across Escambia County, Florida, where snow fell in Molino and flurries were reported as far south as Miramar Beach, Destin, and Pensacola, the latter location of which received a trace of snow. Ice on a U.S. Route 29 bridge between McDavid and Century killed one person, and there were also several other vehicle crashes near the bridge. Boat parades were cancelled across western Florida due to heavy rainfall, including parades in St. Petersburg and South Pasadena. Temperatures reached a high of 48 F in St. Petersburg, and 61 F in Miami. The cold temperatures resulted in 16 cancelled flights and an additional 121 being delayed at Tampa International Airport. A level 2/slight risk for severe weather was issued by the Storm Prediction Center on its Day 1 Outlook on December 8 across portions of western Florida, which also included a 5 percent tornado risk. A squall line developed along a cold front that moved through western and southern parts of the state, producing high wind gusts and causing $50,000 in property damage. A funnel cloud was also reported in Miami-Dade County.

There were 660 power outages across the Greenville, South Carolina area, and the highest snow fell in South Carolina near Cedar Mountain, where 9 in of snow was reported.

Mid-Atlantic
In Maryland, athletic events in Baltimore were postponed, along with school activities in numerous other counties. In preparation of the winter storm, Baltimore Department of Transportation crews were deployed, spreading more than 18,000 tons of salt across Baltimore County. Winter weather advisories were issued for portions of Maryland and Washington, D.C., and winter storm warnings were in effect for southern Maryland. Snow fell in December across Washington D.C. for the first time since 2013, and snowfall records were broken at several locations across Maryland and Washington, D.C., including at Baltimore/Washington International Airport, Dulles International Airport, and Ronald Reagan Washington National Airport.

Public school activities across several cities were cancelled in Virginia, including in Fairfax and Alexandria, the latter of which also cancelled an ACT test across the city's school district. The heaviest snow across the state fell in Henrico County, where Laurel received 5 in of snow. Two people were killed after a car crash, and there were more than 200 vehicle crashes across the state, including one which shut down all lanes of Georgetown Pike after power lines were downed. About 18,000 power outages occurred across Virginia, including 3,500 across northern portions of the state. The winter storm also caused $95,000 in property damage.

Northeastern United States
Prior to the winter storm, speed restrictions were implemented along the New Jersey Turnpike, Garden State Parkway, and Delaware River bridges, and Six Flags Great Adventure was closed in Jackson, New Jersey, along with a planned attempt at a world-record-breaking snowball fight there. In New Jersey, the majority of the state was under a winter storm advisory, while five counties were under a winter storm warning. A nine-vehicle crash closed a ramp to U.S. Route 422 in Tredyffrin Township, Pennsylvania, while another vehicle crash closed a lane of Interstate 95 in Pennsylvania and caused delays. Philadelphia broke its daily snowfall record on December 9, receiving 4.1 in of snow, surpassing the previous record set in 1942. Prior to the winter storm impacting New York, two facilities at Fordham University were closed. Central Park received 4.6 in of snow, and New York City received its first major snowfall of the 2017–18 winter season.

A speed restriction was implemented on the Massachusetts Turnpike, as vehicles slid off the Turnpike in Framingham, Massachusetts. More than 2,100 crews were deployed by the Massachusetts Department of Transportation to treat roadways across the state, and nearly 300 equipment pieces were deployed by Worcester, Massachusetts, Department of Public Works. A parking ban was implemented in Worcester. Across Massachusetts, the highest accumulation fell in Framingham, where 7.5 in of snow fell, while Arlington, received 7.2 in of snow. Boston received 6.1 in of snow, and numerous vehicle crashes occurred across Massachusetts, with several people being hospitalized. A parking ban was also in place in Hampshire County, Massachusetts, where 65 vehicles were towed in Northampton. There were also three vehicle crashes in Hampshire County. In Connecticut, about 354 vehicle accidents occurred in nearly a 24-hour period, including 31 crashes with minor injuries. There were also about 228 motorist incidents, and numerous crashes occurred across Bethel, Greenwich, and Ridgefield, Connecticut. There were also several vehicle crashes and incidents of vehicles sliding off roads across Maine, including in Bangor and Auburn. Delays occurred at airports across the Northeast, including at Newark Liberty International Airport, John F. Kennedy International Airport, and Philadelphia International Airport.

Germany and Switzerland
In southern Germany, wind gusts of 122 km/h occurred in Waibstadt, and there were reported winds of over 100 km/h in Munich. Blowing snow and high winds contributed to numerous vehicle accidents across the Black Forest, and in the districts of Dachau, Fürstenfeldbruck, and Starnberg. Felled trees caused train delays in Munich and Stuttgart, and a crane collapsed in Germering as a result of the high winds. Flights were reportedly disrupted at Munich Airport, including one being cancelled, and eight people were injured.

Severe weather and high winds in Switzerland caused numerous felled and uprooted trees, some of which obstructed roads, and property damage in Baselland. A woman was killed in after high winds a tree fell on her while in a tent, which injured another person inside. High winds also overturned barriers at multiple construction sites, and felled a tree onto a moving vehicle. Fallen trees blocked transit lines in, and numerous calls were made to Baselland public safety for assistance.