January 21, 2016

Blizzard 2016: Frequently Asked Questions, Answered

Q: How much snow am I going to get?

A: Here's a snowfall forecast issued on Thursday morning and valid through Sunday morning.



Q: Where do I live on that map?

A: https://www.google.com/maps

Q: Yeah but how much snow am I going to get?

A: Your town could get 8-12" of snow from this storm, less if ice mixes in.

Q: Yeah but how much snow will we get exactly???

A: Did I stutter?

Q: lol okay really though what's really going to happen are they hyping this?

A: No, this isn't hype, and what you see in the forecast is what they really think is going to happen. Weather forecasting isn't a grocery store—we don't keep the good forecasts in the back, and we don't benefit from hype since our reputations are on the line. Hype is driven by the management side of news operations that care more about ratings/revenues than the true newsworthiness of an event.

Q: When will the worst happen?

A: Friday through Saturday

Q: Is this really the worst storm that's ever happened?

A: This storm has a chance to break snowfall records in several places. It could be one of the top two or three storms ever recorded in Washington D.C., for example, and if it stays all snow, cities in southern Virginia and North Carolina could come close to breaking all-time records.

Q: When was the last time we had a storm like this?

A: The last time you had a storm this bad in the Mid-Atlantic was during the blockbuster blizzard fest during the winter of 2009-2010, when you had something like three major snowstorms in a one- or two-month window. Farther south, with an exception here or there, this is probably going to be the biggest storm since the Blizzard of 1996, if not earlier than that.

Q: I have a flight out of Dulles at 8:30 PM on Friday.

A: Not anymore.

Q: Will the next flight be cancelled?

A: Yes.

Q: What about Saturday?

A: Yes.

Q: When will the airports reopen?

A: It's not so much an issue of the airport being closed as it is the airlines cancelling all of their flights. Airplanes and frozen precipitation don't play well together, and airlines aren't thrilled with the sight of planes full of people falling out of the sky.

Q: will skol b closd 2mrw?????

A: For your sake, I hope not.

Q: I wish I had a job where you could be wrong all the time and still get paid!

A: I hope your pants rip when you're far away from home.

Q: If the high is going to be 27°F, why are we expecting freezing rain instead of snow?

A: There's a shallow layer of warm air a few thousand feet above the ground, completely melting the snowflake before it reaches the ground. The melted snowflake—a raindrop!—re-enters the subfreezing air at the surface and freezes on contact with anything exposed to the elements.

Q: Why is it hailing?

A: It's sleet. Sleet forms through the same process as freezing rain, but the snowflake doesn't completely melt. The remaining ice crystals in the raindrop give the water a nucleus around which to freeze, solidifying the droplet into a tiny ice pellet, or sleet.

Q: My friend's cousin on Facebook said that we're gonna get a—

A: Ignore him.

Q: But my friend says that he's never wr—

A: Ignore. Him.

Q: The Virginia Snowstorm Action Authority 3000 Facebook page said that we're gonna get—

A: That page is also run by your friend's 12-year-old cousin. Ignore it.

Q: Is this El Niño making landfall?

A: That question makes me want to take up drinking.

A Dusting of Snow Is More Dangerous Than a Foot of Snow

Washington D.C. fell apart in the snow on Wednesday night. No, it wasn't the big blizzard everyone's freaking out about. A passing disturbance dropped an inch of snow, and not even an inch in some spots. Yet at midnight the traffic map still shows complete gridlock from Stafford County north into Baltimore, east to the Bay and west to Dulles Airport, hours after the snow stopped falling.

As we've seen time and time again from cities across the country, a dusting of snow is often more dangerous than a foot of snow. You're more likely to get stranded on the side of the road after an inch of snow than you are after a major snowstorm.

Think about the logistics of driving during or after a big snowfall. You'd have to make your way to your car, dig your car out, clean off enough to see, manage to get out onto the roads, and hope that every road between point A and point B is passable. This is plausible for people with large vehicles that are able to traverse somewhat deep snow, but most people have regular cars that would sit and spin their tires in snow half as deep.

Now consider a dusting of snow, sometimes not even deep enough to cover blades of grass or obscure the roadway. Most people facing this situation wouldn't hesitate to hop in their car, flip on their wipers for one cycle, and head out at highway speeds. When a light coating of snow—about an inch or less—falls during the day, schools and businesses will rarely grind to a halt. They'll let out at normal time and cancel after-school activities. Employers are unlikely to let their employees go home early. The day proceeds as normal.

This scenario usually leaves tens of thousands of cars flooding onto local roadways all at once at rush hour, casting their heat onto the fresh sheet of snow below. The heat melts the snow, which quickly freezes into a glaze of ice if temperatures are below freezing. Vehicles and ice don't mix. People spin out. People crash. People get stuck. All traffic on almost all roads slows to a crawl or stops altogether.

That is not a hypothetical. That is what happened in Washington D.C. on Wednesday. That is what happened in Raleigh the day of the infamous "flaming snow car" incident. That's what happened in Atlanta and Birmingham back in January 2014 when tens of thousands of people were trapped on the roads overnight after a quick couple of inches of snow came in a few hours earlier than forecast, forcing children to spend the night at school because buses and parents couldn't make it there to bring them home. It's not even an issue confined to the south or east—the beginning of winter, especially, brings regular stories of pile-ups in the northern U.S. from people not being used to the snow. Nobody is a good driver in the snow. You just get used to it.

We always hear after a plane crash that there's rarely one single cause behind the accident. The plane wrenched into the ground at 400 MPH because of a chain reaction of failures. Society crashes into a ditch for the same reason—it takes many converging factors in order for a disaster to unfold. Poor forecasts (which were not a cause in this instance) can contribute, as can poor judgement on the part of decision-makers, untreated roads, and people not being able to handle their multi-ton vehicles on a surface with no friction.

Trafficpocalypse 2016 will not happen again on Friday. A well-forecast event like the one expected to pound the Mid-Atlantic this weekend will prompt just about every school district and government in the line of fire to close their doors before the first cloud moves in. The grocery runs for those all-important milk sandwiches will go down in the hours before the storm. These large storms cause problems on another level—power outages, property damage, first responders delayed in answering calls, people not being able to leave home for a few days. But there's the key: people will stay home! 95% of the time, storms with appreciable accumulations of snow don't come as a surprise in this day and age, and people make appropriate plans to deal with it.

A dusting of snow doesn't command the same deserved level of respect as six or twelve or twenty inches of snow. Even though it seems embarrassing to admit in the face of so much ridicule from macho keyboard warriors, a dusting causes a unique set of problems you don't face in deeper snow. It doesn't matter what we should be able to handle, it matters how people and vehicles and roadways actually react with such small amounts of snow, and it's pretty hard to drive on the resulting sheet of ice.

January 19, 2016

Blizzard 2016: Prepare for Zero to Thirty Inches of Snow or Ice or Rain


The breadbakers and cows of America are proud to present the blockbuster feature of Winter 2015-16, an event to rival all model-simulated events, one that will result in the highest number of breathless street interviews since the release of the iPhone. We have rounded the corner and there is no turning back. The snow machine is turned up to eleven. This, my friends, is Blizzard 2016. Cue the dramatic music.

'Blizzard'


The term "blizzard" has a very specific definition. A blizzard occurs when 35+ MPH winds create blowing snow that limits visibility to one-quarter of a mile or less for at least three consecutive hours. In other words, a blizzard is essentially a whiteout. There's a chance that someone somewhere could see blizzard conditions, but it's hard to achieve and not yet a guarantee. In lieu of using my beloved "Skittlebip" names (or, heaven forbid, using Winter Storm Chirple or Tupp or whatever they're calling this one), I've decided to use the delightfully retro and dramatic "Blizzard 2016."

The Setup


Admire Tuesday morning's GFS forecast for the jet stream on Friday evening. Ohhhh:



And here's the same step from the same run of the same model showing the surface low sitting off North Carolina. Ahhhh:


The condensed version of the setup is that a trough coming ashore in the Pacific Northwest right now will allow for the formation of a low pressure system near the Texas Panhandle on Thursday. Over the next couple of days, a jaunty upper-level trough will develop, feeding the low ample lift as it saunters across the southern states toward the East Coast. The low will exit stage right over North Carolina, slowly turning northeast and paralleling the coast as it drags in cold air from the north/west and warm air from the south. 

The global models have been strikingly consistent over the past couple of days in that a storm will form. I'm usually the first one on Twitter screaming that you shouldn't listen to the hype and everything is super uncertain, but the odds look pretty good that there will be a storm and that someone will get buried, we just don't know specifically where or how much. Y'know, the important stuff that people want to know. Fun!

Likely Impacts


Here's a snapshot of how things stand as of Tuesday afternoon. It can and will change as we get closer to the event and models and humans get a better handle on what will happen.

WHO: This storm will occur in two phases; the first dropping some snow and ice as it swings across the Midwest and Mid-South. The system will probably drop a decent blanket of snow (generally less than six inches) on top of some ice accretion from freezing rain. The main area expecting wintry precipitation is from the AR/MO border eastward through Kentucky and West Virginia. This is different from the other winter storm that's expected to affect the area on Tuesday night and Wednesday. (It's active out there!)

The second phase will be the nor'easter, likely affecting folks from the southern Appalachian Mountains northeast through the Mid-Atlantic and possibly into the Northeast. The likely swath of decent snow/ice from the nor'easter will occur from western North Carolina east to Raleigh and north through most of Virginia and the D.C. area. Once you get farther north than D.C., the impact of the storm is far more uncertain. You could see lots of snow or almost nothing. It's just too early to tell.

In other words, everyone from Asheville to Boston is in play. That's maddeningly unspecific, but we're three to four days from the event. Specifics will get clearer on Wednesday and Thursday. We are predicting the future, after all.

WHEN: The snow and ice from the low moving east across the country will fall on the Midwest and Mid-South on Thursday into Friday, with the nor'easter beginning on Thursday night and lasting through Sunday from south to north. The storm will probably move slowly once it approaches the coast, so an extended period of heavy precipitation is possible in places like North Carolina, Virginia, the D.C. area, and the Delmarva Peninsula.

SNOW: Significant snowfall is possible from western North Carolina through the Mid-Atlantic, possibly extending into the Northeast if the track is farther north. I'd say there's a better than 50% chance that a large area sees a foot or more of snow, and many people within that swath see two or more feet of snow. It'll be a big storm, and depending on where that giant thump takes place, it could be historic.

The exact track of the storm is key for snowfall, as its movement will determine where the deformation zone sets up shop—the "comma head" in the storm that hosts the heaviest bands of precipitation that sit and dump many inches of snow an hour. Its track will also determine where the rain/ice/snow line sets up. Someone will get a lot of cold rain. Someone will probably see a significant ice accretion from sleet and freezing rain before switching over to rain or snow. Someone will see two or more feet of snow. The distance between these three weather conditions will not be great—maybe a few dozen miles.

TRAVEL: Expect airport closures and flight cancellations anywhere heavy wintry precipitation falls. Several hubs will be affected. The hardest-hit areas will see cancellations last for days. Train service will cease for a large area until the tracks are cleared. Public transit will shut down completely or operate on a severely limited schedule. Roads will be impassable during the worst of the storm, and crews will likely struggle to keep up with plowing. Side streets will remain snow covered until crews can clear main arteries. If you have to go out driving, make sure you have supplies in your car to keep warm, communicate, dig yourself out, and feed/hydrate yourself for a day or more.

Make alternate plans for travel if you have a pretty good feeling that your flight/train/trip won't happen as you hoped it would.

POWER OUTAGES: Heavy snow, ice, and wind are a recipe for widespread power outages. Make sure you have food, water, first aid supplies, batteries, and sources of warmth (candles and blankets, especially) to last a couple of days. Keep some cash on hand, too, so you can buy things if necessary. Plastic doesn't work if the power's out.

PETS: Don't leave your pets outside. Bring them inside. Read them a book. Pet them.

COASTAL FLOODING: The strength/duration of the storm combined with a full moon will lead to coastal flooding and beach erosion, all of which will be worse at high tide. Coastal communities are (well, should be) well prepared for this type of an event, but be mindful of the potential for impassable roads and a storm surge if you're on the coast during this storm.

STRUCTURAL DAMAGE: Snow and ice are heavy. Large accumulations can strain damaged roofs to the point of cracking or completely giving in. Look out for signs of stress or damage to your home, and avoid box stores (especially older ones) if you can. If you're a store after the storm and hear loud metallic creaking above you, it's probably a good idea to tell someone and then leave.

SCHOOLS: This is a kid's nightmare, unfolding on a Friday and Saturday like this. For shame. Snow on a weekend probably limit the amount of school closings come next week. Areas that experience the heaviest snow will probably still have at least a snow day or two next week. 

Worst Case Scenario


Let's speculate wildly, giving people juicy tidbits to quote out-of-context next to extreme snow maps on social media. Say that the worst case scenario occurs, which is actually the best case scenario for snow lovers. There are really two worst case scenarios here.

The first is the most obvious, one in which Washington D.C., Baltimore, and Philadelphia crack into their top ten all-time snowstorms. Many suburbs would see two or more feet of snow, with some lucky spots approaching three feet. Even though the storm would go down on Friday and Saturday, schools would close on Monday and Tuesday, if not longer. Airports would be closed during the storm itself, with residual cancellations in the thousands for days after the storm. Power would go out for many as wet snow and strong winds stress trees and power lines to their breaking point.

The other worst case scenario is one that Tuesday's 12z run of the European model showed, slamming southern/central Virginia and North Carolina with more snow than they've ever seen from any single storm in recorded history. This latter scenario, which would be a complete disaster for the area, is far more unlikely than the former.

But again, that's just the worst case scenario. Consider that only a couple of times in recorded history have storms produced more than two feet of snow in these cities. Their suburbs are another story, but it's still a rare event that requires the stars and the planets and the jets and probably some inside-out pajamas to achieve.

Back to Reality

Come back to the real world for a little while. Like a nervous flier embarking on a cross-country trip, it's time to meticulously ponder all of the things that could go wrong. Dry air. A jog east. A jog west. All rain. Sleet mixing in. It's enough to make a snow lover want to cry.


  1. We know the storm will more than likely happen. We're not too sure exactly where the storm will go. If you live in Washington D.C., for instance, and the storm goes a bit farther north than many of the models are showing, then you'll have an extended period of rain or ice before changing over to snow. This would severely limit snow accumulations and create a whole new set of problems.

    If you live along the rest of the I-95 corridor between there and New York City, what will happen is even more up in the air, because if the storm treks farther south than predicted, you might get very little to no snow. On the other hand, if it goes farther north, you could get slammed with the full might of a top-ten snowstorm.

    Track is everything.
  2. In addition to track, an unexpected intrusion of warm air a few thousand feet above the surface could also wreak havoc on a forecast, leading to much more ice or plain ol' rain than forecasters initially expected. This is more likely on the southern periphery of the storm, in places like the Delmarva Peninsula, southeastern Virginia, and North Carolina.
  3. A big storm like the one models are showing has a bigger opportunity to ingest dry air, which leads to a snow lover's dreaded "dry slot." If dry air seeps into the storm, it could significantly cut down on snowfall totals in the areas cut off from the rest of the precipitation.
  4. Any sleet or freezing rain/rain that mixes in will compact snow that's already on the ground, leading to the potential for solidification after a cold night. Snow that freezes into a sort of glacial ice is extremely hard to remove once it freezes, so sidewalks, parking lots, and streets that aren't cleared immediately may not be cleared for a while.

Cool Down


We'll know more in the coming days. We're still four full days from the worst of whatever happens. Snow lovers are extra anxious over this storm, teetering on the edge of militant wishcasting, which just sets them up for an even greater disappointment. People are being oddly combative about the storm on social media, overreacting to the typical doom and gloom and hype peddled by less-reputable (or ratings-driven) sources. It's going to happen the way it happens. It's not like we've never had snow before, and it's not like a snowstorm has the same stoic urgency as a hurricane swirling ashore or a tornado approaching a city. In the grand scheme of self-inflicted dangerous situations, a foot of snow is arguably less dangerous than an inch of snow, because fewer people are dumb enough to venture out in snow up to their shins than they would if the curb is still visible. Big storms like this become a problem of 21st century logistics (say, first responders getting to a call) than the 100-car pileups much smaller storms are famous for causing. 

Everyone should lighten up a bit. You're not that important—your Tweets aren't life or death. You're largely preaching to the choir. People will get the memo. They'll find out on their own that the storm is coming—in all likelihood, your Tweets won't keep someone from getting stuck on I-95 who then has to resort to eating their steering column to survive the long, harsh night. Lord knows anyone who needs to go grocery shopping will wipe the stores clean once they see the snowflake on their weather apps. This is a situation where there's lots of lead time, so hopefully vulnerable populations will have plenty of time to prepare or seek help as well.

We'll get through it. We always do. Don't go driving, don't go flying, don't shovel more than your ticker can handle, and don't stand under an old, creaky tree. As long as you're prepared for the things you can't control (like a power outage), you should be fine.

[Top Image via The Simpsons/YouTube | Weather Models via Pivotal Weather]