Boiling water turns into flash-frozen snow at -33C

Yan sez, "It was really, really cold outside today (-29°F/-33°C) (With the wind chill factor), so I decided to use the opportunity to show my kids what happens when you throw really hot (boiling) water in the air outside at this temperature. Just seeing the look of wonder on my kids' faces was all I needed to justify going outside today."

It’s really cold outside today here on the south shore of Montreal (QC, CA). Really, really cold. The temperature outside currently is at -13°F (-25°C), but when you add in the wind chill factor, it feels more like -29°F (-33°C). Since it rarely gets this cold, I decided to use the opportunity to show my kids what happens when you throw really hot (boiling) water in the air at this temperature. You can check out the video of the experiment below (and put it in HD and full screen mode to observe the effect more closely.)

Turning Boiling or Hot Water into Snow at -13°F (-25°C) [Video] (Thanks, Yan!)


  1. I am furious that I grew up in Central Alberta, where 6 week periods of -40C were common in the winter, and nobody ever showed me this.  Awesome.

    1. That’s really a bit depressing. I have a friend who travels quite a bit for work. This is the first thing he does after arriving in the frigid part of Alberta during winter time. I now associate the whole concept with Canada in general.

    1.  No, not sadly – this is fine to see on video from the warmth of “not there”.  I was 230km north of where this was shot, and the temperature and windchill brought it to -44C.  It’s like football – watching is better than being there :-)

  2. I can live with the disappointment of not getting to do this, in exchange for the joy of not having to live in that weather.  (I live in Arizona.)

    1. I recently spent a few months in Toronto, then flew to Vancouver from Chicago via Phoenix, Arizona. It amused me a lot to hear the workers at Phoenix complaining about how cold it was at 68 degrees. 

      1. Under 85° is cold to me. I wear my BB hoodie to go out to the mailbox in that weather. Super dry climates do make what you consider warm weather feel much cooler.

  3. This type of weather is exactly what I think about when my Canadian wife starts trying to convince me to move back to her hometown.  No thank you!  It’s t-shirt weather where we live right now!  Granted, summer is a different story. Montreal is a great city in the summer, and here?  It’s way too hot.

    1. I’m sure these are the only two people to have performed this experiment in the history of man.

      In all seriousness though, the video you’ve linked to is very cool simply due to the from the ground camera angle.

    1. Yes thank you! Wind chill is totally irrelevant to the demonstration at hand. I’d be curious to know the actual temperature, and if it just need to be below freezing to get this effect.

      1. The actual temperature is on both the title of the video (the youtube video, not Cory’s title) and the description below the video.

        As to your second question, no it needs to be well below freezing to achieve this affect. Remember the larger the difference in temperature, the faster the transfer of heat energy. Throw a pot of boiling water into the air at negative 2 celcius and you’ll end up with very hot water on the ground. An hour or so later you might have a frozen puddle.

        1.  Well, if your ground is paved with a thick layer of aluminium, that puddle’ll be ice in a few minutes.

    2. Windchill does mean something with pure physics.  It is a relative measure of heat loss.  Which means that it effects everything, not just human skin.  The demonstration at hand happens in a short enough time frame that wind is not a factor, yes. 

    3. Human skin is governed by pure physics, just like other things.  When there is a lot of air movement, warm surfaces don’t maintain a layer of warmer air near them (smaller delta-T between object & adjoining air), resulting in greater heat transfer.  This applies to all warm objects, not just humans (that’s why the upwind side of a building is often colder than the downwind side).

      I personally disagree with people referring to the temperature as “-30” when it’s really “-22 and windy” – those are not the same thing.  You don’t dress the same for them, objects without internal heating do not settle at temperatures below ambient, etc.

      1. “I personally disagree with people referring to the temperature as “-30” when it’s really “-22 and windy” – those are not the same thing. You don’t dress the same for them…”

        You certainly don’t. I live in a very windy place and on the odd day that the wind calms down it always feels so damned mild. You only have to go a mile inland and it feels like a totally different climate – on a windy day it’ll feel a lot milder, on a calm day it’ll be cooler (magic of a windy south-coast town). I live in the UK though, so it’s not ‘freezing’ as much as it is ‘meh’, but the effect the wind has should never be underestimated.

        I hate the wind.

    4. You must hate the dew point. But it’s the most useful measure in hot weather. Because evaporative cooling actually changes the temperature of your surface. As do the component parts of windchill, which are best summed up as ‘windchill’.

    5.  I was about to say that. It is not a temperature correction. If you set that pot of water on the porch instead of throwing it, it would reach a final equilibrium temperature of -25 C not -33 C. Wind can play a factor in how fast it reaches that equilibrium temperature but it has nothing whatsoever to do with the actual temperature.

      Correcting the headline would be welcome. This is what comes of all those bananas in the same day.

  4. Tossing boiling water out the door when it is -40°F straight — no wind chill considered –used to be a popular pastime in my Montana town.  Now we are lucky to get below freezing some days!  Can’t even keep the outdoor ice rink frozen.

  5. An acquaintance’s kid just found out the hard way to check the wind direction before trying this one. 

  6. I went to college in upstate New York, and there’d usually be a few weeks of -20F weather in the winter. A rumor that I can neither confirm nor deny says that residents of some of the dorms used to make snow the opposite way – they’d turn the showers in the dorm bathrooms on hot, and once it got steamy enough, they’d open the windows to let in cold air and make the snow there.

  7. Is this really snow, as in the SOLID form of water? It looks to me like the water was merely dispersed to small droplets which then rapidly vaporized to the gas phase of water, which is invisible. You can see this as the cloud of “snow” rapidly dissipates rather than persisting or falling to the ground as snow or ice solids around 22-26 seconds. The snow where I come from doesn’t spontaneously disappear from sight. Further, even small amounts, around 1mL , of room temperature water may take several minutes to freeze in a -80C freezer. I doubt that boiling hot water, almost a gas energetically, is able to lose this much heat nearly instantaneously.

    1.  I’ve been thinking very much the same thing this week as I’ve watched video after video of people creating large clouds of vapor and calling them snow.  Where is the snow?!?

    2. Mind you the very small droplets would lose heat very quickly to the air due to their large surface area with respect to their volume. Also the very large difference in temperature between the water and the air creates lots of convection increasing the heat transfer quite a bit. I tried it yesterday and it very well looked like snow, certainly solid by the time it hits the ground. I’ll try to get my boss to bring the high speed camera and shadowgraph outside today to try and get a better look at this.

      1. Mostly EVAPORATION. Check link below.

    3. “I doubt that boiling hot water, almost a gas energetically, is able to lose this much heat nearly instantaneously.”

      FYI Boiling water freezes faster than room-temperature water.

        1. “It all depends on how fast the cooling occurs, and it turns out that hot water will not freeze before cold water but will freeze before lukewarm water. ”

          Good enough for me!

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