Literally blindsided.
Posted on 03/29/2022 12:02:15 PM PDT by lightman
The snow squalls that caused Monday’s 50-car pileup on Interstate 81 that killed five motorists and injured dozens more literally slipped under the radars of the National Weather Service.
A snow squall caused near white-out conditions around 10:30 a.m. when the first crash took place on I-81 north near mile marker 116 in Foster Township. Drivers told reporters they were blinded and their vehicles knocked around as additional vehicles crashed into them.
The National Weather Service had made no observations of snow squalls in the area of the crash in I-81 until it sent out warnings at 12:15 p.m.-1:30 p.m., 12:48 p.m.-1:45 p.m., 1:29 p.m.-2:45 p.m. and 3:06 p.m.-4:15 p.m., according to David Martin, a forecaster with the National Weather Service.
Snow squalls are a brief, heavy burst of snow that comes along with gusty winds and poor visibility, Martin said.
Squalls are dangerous because they can form in minutes, then dissipate or move along to another place unexpectedly. They are difficult to anticipate, and once they are there, hard to escape, Martin said.
“If there is a gap anywhere in central Pa., it is in Schuylkill County down to Lancaster and Lebanon County. They are the furthest from our radar and Philadelphia’s,” Craig Evanego, a forecaster with the National Weather Service, said.
Because of the curvature of the earth, the National Weather Service’s radar beams are only able to detect weather events higher in the atmosphere above spots far from their towers, Evanego said.
Radar visibility is also more limited in spring because storms tend to be closer to earth. In the summer, weather events are detectable higher up, Martin said.
Snow squall warnings are often given just hours in advance when weather conditions align for their formation, as opposed to winter storm warnings which can be predicted days in advance, according to Martin. Because of that, the most forecasters can often do is predict the conditions for a squall to form, and not the squall itself.
“A squall will be in one location one minute, then 30 minutes later be somewhere else,” Martin said.
Meteorologists and other weather experts took to Twitter Monday and Tuesday to discuss a hole in radar coverage over the area of Schuylkill County where the incident on I-81 occurred.
Jesse Ferrell, a forecaster with AccuWeather, said the pileup on I-81 was in a “radar hole”, and that the lowest scan was at 8,000 feet—above the altitude of the snow squall.
Steven Schultze, an associate professor at University of South Alabama, published a map in 2020 showing spots that could be missed by radar.
Adis Juklo, a meteorologist with ABC 27, shared a forecast map indicating radar showed very little over Pottsville where the I-81 pileup occurred. He called for a Terminal Dopplar Weather Radar to be installed in the area to increase that visibility.
Once squalls are in a forecast, Martin recommended drivers should delay any trips and avoid the roads, if at all possible. Once a driver is on the highway, however, they should get off at the nearest exit, he recommended.
Pulling off onto the shoulder of the interstate is dangerous, according to Martin, because another vehicle might hit yours.
“If you can’t pull off safely, proceed with very much caution and be very careful. Don’t stop in the middle of the road—that can cause major problems,” Martin said.
PennDOT might also use road treatments to help the situation.
“Things can be done—there’s just not a lot of time,” Martin said.
The National Weather Service’s State College office issued 16 squall warnings Monday, one of the highest number of such warnings in the four years they’ve been issued, according to Martin. Snow squalls accounted for 14 warnings during a similar storm on Feb. 19. That 40-car pileup that injured five people also occurred on I-81, about 25 miles northeast of Monday’s pileup but still in Schuylkill County.
“It would be in the top three, if not at the top since we started issuing them,” Evanego said of the snow squall warnings Monday. “It’s definitely one of the most widespread events we’ve issued snow squall warnings for.” Sample HTML block
Literally blindsided.
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Video of the pileup as it happened
The radar coverage gap also affects Adams, York, Lancaster, and Lebanon Counties which have sometime been referred to as “Pennsylvania’s Tornado Alley”.
Strong convective thunderstorms moving east or southeast pick up a shot of energy from the urban “heat islands” plus a shot of moisture from the mile-wide Susquehanna leading to rapid intensification.
Unfortunately that area is on the fringe of the Sterling VA, Mt. Holly NJ, and State College doppler radars.
WE REALLY NEED DOPPLER AT HIA!
All my life northerners told me that they're experts at driving in snow. LOL
Substitute Squall for 0 visibility FOG bank that hits when you're driving 65 miles an hour on a crowded interstate and are effectively immediately blinded like someone covered your windshield.
Wow, not good.
The person who drove their car off to the side had the right idea.
I would have gotten out of the vehicle and ran out of the area.
The idiot who backed his car up back into the lanes - is an idiot.
Yep. This wasn’t about road surface conditions as much as it was about visibility
Driving too fast for conditions.
Virtually everyone.
Just stupid.
BINGO...and visibility can drop from a mile or more to ZERO in seconds.
Skies were perfectly clear in the areas outside of the squalls yesterday.
I just talked to someone who came back from Philadelphia and he said on the weekend he got hit by a brief pocket of heavy son.
Anybody going 80 mph with any amount of snow are idiots.
Yep, that's when you realize you are going 65 miles per hour and you want to stop or pull over, but you can't see the road.
Re: 6 - Fog can be deadly:
https://www.cbc.ca/news/canada/windsor/highway-401-fog-crash-1999-windsor-manning-road-1.5267759
https://en.wikipedia.org/wiki/1999_Ontario_Highway_401_crash
As a general rule, it can be a zoo on Provincial highways. I was hit from behind by a driver on the 403 just east of McMaster University. The moron slowed down, stopped for about 30 seconds then sped off, belching blue smoke. He broke down about 1 mile away with his Dodge Charger seriously wrecked - the car I was driving was totaled. The OPP officer told me it would have been much worse if it was a regular work day. Luckily that day was the May Two-Four, so very light traffic - except for the drunk who hit me.
Yep. I see it every snow storm. Too many people just won’t slow down. And..... bang.
They don’t even slow down in heavy fog with icy roads. We had a 100 car pile up a few years ago. 100ft visibility fog and black ice. They had the drivers on camera blowing by a UHP cruiser, parked with the lights on and flares deployed. Car after car just whizzed by followed by a bang a few seconds later. No one killed though. It was actually pretty funny.
It’s like ground fog in CA or one of those sudden blinding rainstorms in Florida.
It comes out of nowhere, and suddenly you can’t see a thing.
Or smoke on I-44 in Oklahoma.
There is limit to antilock brakes, everyone driving should explore that in empty parking lots without the parking curbs and speed bumps.
Freezing Fog and Snow Squalls is what makes the I80 corridor dangerous from Chicago to Erie. The flatness of IL, IN, Michigan and Ohio do breed a lot of inattention to drivers who do not realize a 30 foot elevation drop is a valley to cold air rolling down a hill. Once PA is reached drivers have been going 85mph for better than 5 hours on clear march days.
Very cheap Technology can solve this with freezing roadway and bridges signs and a simple If people would just reduce their speed with road temperatures 33 - 25 degrees even snow on the roadway isn’t that big of problem at below 25 degrees.
Northern drivers should know by experience sound, feel, sight if the roads could be freezing.
https://www.rikasensor.com/rk500-55-non-contact-road-condition-sensor.html
With multipurpose signs variable speed limits could be established. A 45 mph speed limit through this area would probably not have saved people from collisions in these conditions, would have reduced heavy accidents. A 35 mph, stopped traffic and ice ahead warning would have made this a non event.
With each mile of interstate costing somewhere in the range of million dollars per year to maintain and lifecycle, 60k in signs and sensor tied to IoT in the vechicles is cheaper than car insurance.
https://blog.midwestind.com/much-cost-maintain-mile-road/
https://safety.fhwa.dot.gov/provencountermeasures/variable-speed-limits.cfm
This also proves there is a place for Waze and CB radios in everyone’s earshoot.
They can’t see or predict a snow squall within two hours but they can predict man-made climate disruption 10 years from now? That’s what they call science.
Weather guessers
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