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Ottawa gets more that double the snowfall Helsinki gets. Helsinki gets around 80-100 cm a winter. Though Helsinki sees snow quite frequently, a normal snowfall is light and accumulates just a few cm at a time. To get lake-effect snow it must be a strong cold S or SE system, and those are not very common. This time of the year, like last week, lake-effect snow didn't happen, as it was so moist and the soil not cold enough. So the Baltic warmed up the air so that it fell as sleet or rain without accumulating, while turning to snow only some 70 km inland. In Ottawa, this would've fell as snow.
The Gulf of Finland is only 80 km across and quite shallow, so by late January it starts to freeze over, eliminating the lake-effect. To add, February and March both get on average 37 mm of precipitation (including snow), so it's rather dry in Helsinki then. In Ottawa, it snows quite heavily these months.
Helsinki is dominated by westerlies, and from that direction the air masses are often warm. As the 500hPa and 850hPa are around freezing or above, it turns to rain, especially in December. Cold upper air falls down from the Arctic, and that seldom bring heavy snow.
Definitely makes sense about Helsinki. What city do you think has a more continuous and longer lasting snowpack?
Hard to say. Helsinki has a snowpack from around Christmas to late March or early April on average. Maybe Ottawa gets their snow earlier, dunno.
I lived in Ottawa for several years and when the snowpack starts is quite variable from year to year. Normally though, it usually starts in the first part of December and stays until the end of March, so it looks like it lasts a bit longer than Helsinki's.
As someone sitting just across the bridge from Canada's capital, I have to say Ottawa takes it with an average of 220 cm per winter.
As for snowpack, I would be surprised if Helsinki had more and for longer as it gets oceanic mild periods that bring rain and melt the snow. Ottawa gets mild periods and rain in the winter too but not so much as it is inland.
That said it is possible to have a city with much less snowfall than another to have longer annual snowpack periods. I am pretty sure many of the colder Prairie cities like Winnipeg and Regina (average snowfall of barely 100 cm) have snow on the ground for much longer than places on the east coast like St. John's which get more than 300 cm, but also get tons of rain (often in the same storm) that melt a lot of it away.
This is not the case for Ottawa vs. Helsinki though.
I lived in Ottawa for several years and when the snowpack starts is quite variable from year to year. Normally though, it usually starts in the first part of December and stays until the end of March, so it looks like it lasts a bit longer than Helsinki's.
Yes, the snowpack start and end dates for Ottawa can vary a lot. Going from memory the earliest I have seen was Nov. 1 about 20 years ago. The latest was the first week of January. If I had to pick an average date it would be around December 10.
Eight out of 10 years might have a bit of snowfall in November but with no snowpack taking form in that month.
Snow that falls in December before Christmas often melts as well.
Some years Ottawa may also get a "January thaw", usually around the 10-15th of the month. This sometimes brings temperatures of +5C or even slightly higher as well as rain. If the rain is heavy and the snowpack is not too deep you can start to see the grass again in some places. But this is usually followed by the coldest air of the winter and more snow.
In my experience the snowpack is generally gone by the official first day of spring around March 21. Except maybe for huge piles in large parking lots. Once of out of every 10 years the snowpack lingers into April, sometimes at late as the 10th. In milder years with little snowfall much of it can be gone by the first weeks of March though.
Yes, the snowpack start and end dates for Ottawa can vary a lot. Going from memory the earliest I have seen was Nov. 1 about 20 years ago. The latest was the first week of January. If I had to pick an average date it would be around December 10.
Eight out of 10 years might have a bit of snowfall in November but with no snowpack taking form in that month.
Snow that falls in December before Christmas often melts as well.
Some years Ottawa may also get a "January thaw", usually around the 10-15th of the month. This sometimes brings temperatures of +5C or even slightly higher as well as rain. If the rain is heavy and the snowpack is not too deep you can start to see the grass again in some places. But this is usually followed by the coldest air of the winter and more snow.
In my experience the snowpack is generally gone by the official first day of spring around March 21. Except maybe for huge piles in large parking lots. Once of out of every 10 years the snowpack lingers into April, sometimes at late as the 10th. In milder years with little snowfall much of it can be gone by the first weeks of March though.
Helsinki's snowpack can definitely last as long as Ottawa's if not longer, and October snowfall isn't rare. They've seen October snow around 5-6 times in the past 12 years. You can check the depths on the page before this but I haven't completed October yet so I have left some blank
(October 2005 saw 5cm as well)
Yes, the snowpack start and end dates for Ottawa can vary a lot. Going from memory the earliest I have seen was Nov. 1 about 20 years ago. The latest was the first week of January. If I had to pick an average date it would be around December 10.
For Helsinki the earliest ever is 28 October 1941 and the latest 2 March 2008. If March doesn't count the latest is 22 February 1925.
Helsinki Centre has seen September snowfall once, Helsinki Airport twice.
Helsinki see January thaws hardly ever, but the snowpack can take well into January before it starts to form.
Quote:
Originally Posted by Rams_Lord
Helsinki's snowpack can definitely last as long as Ottawa's if not longer, and October snowfall isn't rare. They've seen October snow around 5-6 times in the past 12 years. You can check the depths on the page before this but I haven't completed October yet so I have left some blank
(October 2005 saw 5cm as well)
October can well see snow, like as in 2012, but it doesn't mean the snowpack will start to form then, as it melts away in a couple of days.
Now I am coming back to seeing the many similarities. Especially with Finland.
We are the snowiest and the most continental one.
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. You can check the depths on the page before this but I haven't completed October yet so I have left some blank
If March doesn't count the latest is 22 February 1925.
