Before and during the crippling snowstorm that brought traffic to a standstill on Interstate 95 on Jan. 3, the National Weather Service made information available about the heavy snow threat to the Virginia Department of Transportation on multiple occasions.

Hundreds of vehicles were stranded on I-95 between Jan. 3 and 4 near Fredericksburg, some for over 24 hours without food, water and other essential supplies.

Materials provided to The Washington Post by the Weather Service show that VDOT was sent forecast information and invited to briefings in which the strong possibility of heavy snowfall was conveyed. VDOT was also briefed about the storm threat by DTN, a private company based in Minnesota that does forecast consulting for transportation agencies, among other customers.

Weather Service offices in Sterling and Wakefield, Va., which cover northern and central parts of the state, both emailed briefing materials to VDOT and included them in video conference calls.

The Weather Service provided to The Post a list of 14 briefings it provided to partners, including emergency management, local governments and transportation agencies on Jan. 2 and 3.

The forecast office in Wakefield first emailed briefing materials to these partners about the chance of significant snow and its potential intensity early in the morning on Jan. 2.

At 2 p.m. on Jan. 2, the Sterling office delivered an online briefing to the Metro Area Transportation Operations Committee, which includes VDOT’s Northern Virginia district and other D.C.-area transportation agencies.

A representative from VDOT’s Northern Virginia district attended the 2 p.m. briefing, said Ellen Kamilakis, its acting communications manager.

Christopher Strong, the Sterling office’s warning coordination meteorologist who delivered the briefing, said he “leaned very heavily on not just what was most likely, but also the reasonable worst case for planning.”

Strong said he showed the transportation committee its snowfall projections, which at the time called for most likely amounts between 5 and 8 inches around Fredericksburg with a worst case of 8 to 12 inches. Fredericksburg ultimately received about a foot.

Strong said he mentioned that rain would precede the changeover to snow, that snowfall rates of 1 to 3 inches per hour were possible at the height of the storm and that extremely cold temperatures would follow.

“The National Weather Service forecasts for the Mid-Atlantic snowstorm on January 3 were timely and accurate,” Strong said in an emailed statement. “We issued watches and warnings in advance, beginning early Sunday morning (Jan. 2), all highlighting hazardous road conditions for the entire metro DC area north to Baltimore and south to Richmond.”

A family bound for a beach vacation and a trucker headed to Georgia were among hundreds of drivers stranded for hours on Interstate 95 in Virginia. (Lee Powell/The Washington Post)

VDOT’s Kamilakis said the agency had “no issue” with the Sterling office’s forecast. “It was well within range,” she said in an interview. “We had started conversations [with the Weather Service] on Saturday. On Sunday, [the forecast for snow] started increasing. NWS kept in touch with us.”

VDOT’s Fredericksburg district relied less on the Weather Service and more on DTN, according to Kelly Hannon, communications manager for the district.

“We did not have a briefing [from the Weather Service] on Sunday; however, we looked very heavily at custom forecast information that’s really tailored to the business of transportation,” Hannon said.

Lori Johnson, communications manager for DTN, said that it provided VDOT with weather briefings on Jan. 2 and 3 at 10 a.m. and that hourly updates were available online.

The DTN forecast provided at 10 a.m. Jan. 2 called for “high snow rates” up to 1.5 to 2 inches per hour on the morning of Jan. 3. “By the time snow ends, accumulations of 4-8 inches are forecast for most of northern and western Virginia with a few 10-inch reports possible,” the DTN forecast said.

The DTN forecast informed a news release from the VDOT Fredericksburg district issued at 3:30 p.m. Jan. 2 warning residents and travelers about the heavy snowfall potential.

“Residents and travelers are urged to arrive at their destination ahead of the onset of winter weather, and avoid any unnecessary travel once the storm begins,” the release said. “Snow is anticipated to fall at rates as heavy as two inches per hour, severely limiting motorist visibility.”

VDOT’s Fredericksburg district did receive a briefing from the Weather Service office in Wakefield, but not until Jan. 3 at 9 a.m., when the storm was well underway. In a summary of the briefing provided to The Post, the Wakefield office said it told VDOT that heavy snow was “locked in,” that it would fall at 2 to 3 inches per hour, and that amounts would probably exceed eight inches near Fredericksburg.

Hannon stressed how much VDOT valued the information offered by forecasters. “I want to emphasize the respect we have for everyone in that field, both private providers and the NWS,” she said.

Strong said that while he felt like the Sterling office provided solid information, “we’re talking with our partners about what things we could’ve done better.”

Strong conceded that there was less lead time for the Jan. 3 snowstorm than is often the case. “We are always trying to give as much advanced notice as nature will let us have,” he said. “Every year it gets better but each event is a little different.”

The outreach the Sterling and Wakefield offices provided to VDOT and other partners is part of the Weather Service’s Impact-Based Decision Support Services initiative to help local officials prepare for major storms and understand the range of possibilities.

Louis Uccellini, who retired as director of the Weather Service on Dec. 31, listed the initiative as one of his top accomplishments for “[e]stablishing a trusted relationship with the emergency management and public safety officials at every government level.”

Some have criticized VDOT for not doing enough to prevent the traffic disaster given the forecast information it was supplied.

“I’m of the mind-set that this was a completely preventable situation,” said Jonathan Porter, chief meteorologist for AccuWeather.

Drone video captured on Jan. 4 shows cars stuck for miles on I-95 in Virginia after a snowstorm caused icy conditions and multiple crashes. (Paul Frendach via Storyful)

Porter said the circumstances called for drastic action, considering the potential for heavy snowfall rates on the heels of a warm holiday weekend when many people weren’t tuned in to the weather forecast. “We were alarmed about it and did everything we could to get the message out,” he said. “We specifically said that conditions would rapidly deteriorate and that highway chaos would ensue.”

AccuWeather’s forecast called for 6 to 12 inches of snow, “[R]oads may quickly transition from wet to slushy to snow-covered in a matter of an hour or so,” its online overview of the storm said.

Porter said VDOT should have shut down I-95 ahead of the period of heaviest snowfall. “We needed travel bans issued,” he said. “Even closing the road for a short time may well have prevented those accidents.”

Looking ahead, Porter said, the incident should spark a conversation on how to confront severe weather. “Hopefully we can get a dialogue going,” he said. “With increasing severe weather impacts from climate change, we have to be more proactive in terms of how decisions are made based on forecasts.”

VDOT has promised a multi-agency review “to address performance gaps and identify ways to mitigate the challenges faced during this incident.”