How United Airlines Turned Denver’s Clear Skies To Snow – The Fascinating Science Behind the Rare Phenomenon

When aircraft descend through below-freezing temperatures and high relative humidity (saturated air), they can create snow. Planes aren’t causing snowstorms – just a localized event – but under the right conditions they do cause snow to form and fall to the ground.

This requires water vapor that’s below freezing but that doesn’t form ice crystals because it lacks the particulates on which to freeze. Then, when the planes descends through the atmosphere, the water vapor forms snow on the aircraft’s exhaust. In addition, the lift around the plane’s wing causes ice crystals to form that previously couldn’t. The aircraft’s exhaust and the rapid pressure change around the wing introduce particles and conditions that allow already supercooled liquid droplets to become ice crystals.

Planes in Denver caused a brief snow shower Saturday evening.

  • Between 6:10 p.m. and 7 p.m. local time on Saturday, around a dozen mostly United flights landed on a north-south runway west of the terminals. The incoming flights flew through the cloud layer and left curved, loop-like radar signatures of light snow.

  • United Express flight 5528, operated by SkyWest, came in from Williston, North Dakota. A snow trail matches that plane’s approach path.

  • The airport was about 17°F with 10 miles of visibility — an no large-scale weather system to produce snow. Yet it snowed.

Similar phenomena have been seen in Chicago and I’ve covered it in Dallas. Planes on approach produced sudden pockets of snow seemingly out of nowhere. There’s snow near the airport and nowhere else. It’s not even chemtrail conspiracies or Jewish space lasers but planes actually controlling the weather.

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community InsideFlyer.com, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

More articles by Gary Leff »

Comments

  1. Fascinating phenomenon and excellent succinct explanation. In fact, I was with you the whole way, and then *BAM* Gary throws in a Jewish Space Lasers reference. Bah! Got me good!

  2. When asked about it, United gave some convoluted story about weather.
    Just another Snow Job from United.

  3. I am executive platinum on American. I travel primarily South Florida to the West Coast. If I think I am going to end up in coach I fly United. Just a better experience with seat back screens and the ability to buy food, Not being able to buy food on a b hour Miami to SFO flight is ridiculous. Definitely not a premium experience. Without screens and food, no different from Spirit.

  4. @Lee

    As a fellow EP, who is settling on PP for next cycle, I must say, the MIA-SFO route is just ‘sad’ on AA–737 recliner in First, no IFE screens (and there are some shills here that will say they prefer that). At least for MIA-LAX, AA sometimes operates Flagship 773, 772, and 787 with lie-flat, but then you’d have to connect to SFO.

    With UA, have you tried their 757 with lie-flat, seasonal, FLL-SFO? That’s a good option, if available. Otherwise, jetBlue has Mint for those routes (from FLL and maybe also MIA to SFO), which may be the best option if you can snag one of the ‘throne’ seats in rows 2 and 4. It was nice when B6 had its ‘partnership’ with AA so you could access the Admirals Club when flying them–alas, that is no more. *sigh*

Leave a Reply

Your email address will not be published. Required fields are marked *