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I'm talking about Snowfall divided by precipitation. I'll be using metric units (cm for snowfall and mm for precipitation).
Asahikawa's Februarys get 131 cm of snowfall with just 51.3 mm of precipitation so ratio = 2.55
Some people don't trust snowfall data for Japan so the second highest value I've found (which is pretty close to Asahikawa's by the way) is Denver's Decembers: 21.6 cm of snow with just 8.9 mm of precipitation so ratio = 2.43
The wiki box for Denver uses the precipitation amounts from Denver International Airport but takes snowfall data from Denver Stapleton which is where the Denver airport used to be. So it's possible that the ratio is lower for Denver.
Here's a map of average ratios for significant snowfalls (at least 2" snow or 0.11" precipitation) in the USA. But I think somewhere in Alaska or northern Canada would beat these numbers. Cooperative Institute for Precipitation Systems
Every winter we have a few days with 0.1 or 0.2" of snow but only a trace of precipitation, which is theoretically an infinite ratio.
I'm talking about Snowfall divided by precipitation. I'll be using metric units (cm for snowfall and mm for precipitation).
Asahikawa's Februarys get 131 cm of snowfall with just 51.3 mm of precipitation so ratio = 2.55
Some people don't trust snowfall data for Japan so the second highest value I've found (which is pretty close to Asahikawa's by the way) is Denver's Decembers: 21.6 cm of snow with just 8.9 mm of precipitation so ratio = 2.43
Anyway the highest will be in a place that is very dry and cold. Those kind of places produce very dry snow, so the snow is not as dense and can attain greater depths with less water content.
So for example Paradise is famous for being one of the snowiest places in the world, but because it's mostly wet snow its ratio is rather low.
The wiki box for Denver uses the precipitation amounts from Denver International Airport but takes snowfall data from Denver Stapleton which is where the Denver airport used to be. So it's possible that the ratio is lower for Denver.
Here's a map of average ratios for significant snowfalls (at least 2" snow or 0.11" precipitation) in the USA. But I think somewhere in Alaska or northern Canada would beat these numbers. Cooperative Institute for Precipitation Systems
Every winter we have a few days with 0.1 or 0.2" of snow but only a trace of precipitation, which is theoretically an infinite ratio.
Based on that website, US cities get a lot more winter rain than I realized. Using 1971-2000 data provided, Chicago (O'Hare) has an average snow to precipitation ratio of around 13.5. Dividing the total DJF snowfall by total DJF precipitation yields approximately 4.6, which when divided by 13.5 means only 34% of meteorological winter precipitation fell as snow in the 1971-2000 period. Using the same method in New York yields statistics that show only 15% of precipitation fell as snow during meteorological winter. Considering that the mean winter temperature in these cities was 25.6 degrees and 35 degrees respectively, I would expect far more precipitation to fall as snow. Is there something I am missing?
Based on that website, US cities get a lot more winter rain than I realized. Using 1971-2000 data provided, Chicago (O'Hare) has an average snow to precipitation ratio of around 13.5. Dividing the total DJF snowfall by total DJF precipitation yields approximately 4.6, which when divided by 13.5 means only 34% of meteorological winter precipitation fell as snow in the 1971-2000 period. Using the same method in New York yields statistics that show only 15% of precipitation fell as snow during meteorological winter. Considering that the mean winter temperature in these cities was 25.6 degrees and 35 degrees respectively, I would expect far more precipitation to fall as snow. Is there something I am missing?
I've noticed that too. I'm not sure why a city with winters as cold as Chicago would get so much winter rain.
I've noticed that too. I'm not sure why a city with winters as cold as Chicago would get so much winter rain.
I did the calculations for a few more cities:
Denver 96%
Minneapolis 83%
Chicago 34%
Boston 27%
New York 15%
Washington 13%
The only thing I can think of is that eastern cities might get much heavier precipitation events during warm days, but it still seems weird that the numbers are as low as they are. Does anyone who lives in a Northeastern or Midwestern American city (or a region with a similar climate) have any idea how so much winter precipitation doesn't fall as snow (or some other explanation of the statistics)?
Warm air can hold more moisture than cold air, so it's probably more likely to rain when it's above freezing. I live in Wisconsin and it's more likely to have rain or snow when it's warm. Cold air usually comes with high pressure and clear skies.
Also it's difficult to have a lot of precipitation when it's very cold. Big snowfalls are normally just below freezing.
Also, Canadian weather stations track rain and snow separately. St John's gets about 50% rain despite an average of -5C in winter. Toronto gets more than half rain in December and February despite an average temperature below freezing. Both of these cities get humid air from the Gulf of Mexico or from the Atlantic Ocean.
Calgary has different weather patterns and doesn't get humid air from the Atlantic or Gulf of Mexico. So it hardly gets any winter rain even though it gets above freezing often. Denver and other places near the Rockies are similar.
That method shows Rochester getting about 68% of winter precipitation as snow. This value seems to make sense as we get lots of snow but also some warm days with rain.
Here's an example of how Lake-effect snow can affect the snowfall percentage. I took five cities in Ontario near Lake Huron and put the weather boxes in one place. https://imgur.com/a/jNld5
Last edited by Crunch41; 10-12-2017 at 10:29 PM..
Reason: added information
Since Barrow beat Asahikawa, I decided to take a look at other locations located in the extreme north.
I found that Mays in Deadhorse have a higher ratio:
5.61/2 = 2.805
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