sun, 17-dec-2023, 14:34

Friday night we got 2.4 inches of snow at home, after a storm earlier in the week dropped a total of 6.9 inches of snow (0.51 inches of liquid). I plowed the road on Wednesday afternoon after most of that first storm’s snow had fallen and got up Saturday morning debating about whether I should plow again. My normal rule is if we get more than two inches I’ll plow, but I didn’t feel like it and left it. It’s snowing again today, so I will probably wind up plowing soon.

Feeling somewhat responsible for keeping the road clear makes winter something of a mixed bag for me because I enjoy the snow in the winter, but the drudgery of plowing turns snow storms into work. I remember plowing three times in the span of a week before Thanksgiving one year, and everyone in Fairbanks remembers Christmas 2021 when we had a major storm with both rain and snow, following by extreme cold, and most people were stuck at home until they could dig out. Our four wheeler was out of commission with a burned up rear differential, so I couldn’t do anything about it.

I thought it would be interesting to look at the storm data for Fairbanks. I’m defining a “storm” as any period with one or more consecutive days with precipitation, and by “precipitation” I mean either rain, or the liquid when daily snowfall is melted. I am not including “trace” precipitation (snowfall less than a tenth of an inch or liquid less than 0.01 inches) in this calculation.

Here’s a table of the top ten storms in Fairbanks, ranked by total precipitation.

Rank Start Days Total Snow (inches) Total Precip (inches) Per Day Snow Per Day Precip
1 1967‑08‑08 8 0.00 6.15 0.00 0.77
2 2003‑07‑26 11 0.00 4.57 0.00 0.42
3 1937‑01‑18 12 38.15 4.17 3.18 0.35
4 1990‑07‑07 7 0.00 3.98 0.00 0.57
5 2021‑12‑25 5 23.39 3.67 4.68 0.73
6 2019‑07‑28 11 0.00 3.59 0.00 0.33
7 2014‑06‑30 3 0.00 3.37 0.00 1.12
8 1948‑07‑18 7 0.00 3.18 0.00 0.45
9 1932‑08‑02 7 0.00 3.14 0.00 0.45
10 1962‑08‑25 6 0.00 3.09 0.00 0.52

A couple storms stand out to me. First, the Christmas 2021 event is 5th on the list (it winds up 13th on the list of winter storms ranked by total snowfall instead of liquid precipitation). It’s so high on this list because a significant amount of the total precipitation in that storm came as rain.

The other remarkable storm for me is the three day rainstorm that started on June 30th, 2014 and ended on July 2nd. We got a remarkable 1.12 inches of rain per day over those three days, and on July 2nd Goldstream Creek went over the banks at our house. Here’s a ranking of storms by average daily precipitation.

Rank Start Days Per Day Precip (inches)
1 2014-07-07 1 1.13
2 2014-06-30 3 1.12
3 2014-09-01 2 1.12
4 1953-06-24 1 1.08
5 1992-07-06 1 0.95

The top three storms are all from the summer 2014.

House surrounded by water

There is evidence that one of the consequences of climate change in Alaska is an increase in the severity of storms. Here’s a ranking of the number of top 50 storms in each decade. The previous decade leads the list, and our current decade already has 2 such top 50 storms. Changing the minimum ranking from top 50 to top 100 doesn’t change the list much, and 2010‒2019 is a the top of that ranking as well.

Decade Number of Top 50 Storms
2010‒2019 9
1920‒1929 7
1930‒1939 7
1940‒1949 6
1960‒1969 4
2000‒2009 4
1990‒1999 3
1910‒1919 2
1950‒1959 2
1970‒1979 2
1980‒1989 2
2020‒2023 2
tags: snow  weather 
thu, 02-may-2013, 07:52
Still snowing

In a post last week I examined how often Fairbanks gets more than two inches of snow in late spring. We only got 1.1 inches on April 24th, so that event didn’t qualify, but another snowstorm hit Fairbanks this week. Enough that I skied to work a couple days ago (April 30th) and could have skied this morning too.

Another, probably more relevant statistic would be to look at storm totals rather than the amount of snow that fell within a single, somewhat arbitrary 24-hour period (midnight to midnight for the Fairbanks Airport station, 6 AM to 6 AM for my COOP station). With SQL window functions we can examine the totals over a moving window, in this case five days and see what the largest late season snowfall totals were in the historical record.

Here’s a list of the late spring (after April 21st) snowfall totals for Fairbanks where the five day snowfall was greater than three inches:

Late spring snow storm totals
Storm start Five day snowfall (inches)
1916-05-03 3.6
1918-04-26 5.1
1918-05-15 2.5
1923-05-03 3.0
1937-04-24 3.6
1941-04-22 8.1
1948-04-26 4.0
1952-05-05 3.0
1964-05-13 4.7
1982-04-30 3.1
1992-05-12 12.3
2001-05-04 6.4
2002-04-25 6.7
2008-04-30 4.3
2013-04-29 3.6

Anyone who was here in 1992 remembers that “summer,” with more than a foot of snow in mid May, and two feet of snow in a pair of storms starting on September 11th, 1992. I don’t expect that all the late spring cold weather and snow we’re experiencing this year will necessarily translate into a short summer like 1992, but we should keep the possibility in mind.

tags: Fairbanks  snow  weather 
tue, 23-apr-2013, 07:01

This morning’s weather forecast includes this section:



Here’s a look at how often Fairbanks gets two or more inches of snow later than April 23rd:

Late spring snowfall amounts, Fairbanks Airport
Date Snow (in) Date Snow (in)
1915‑04‑27 2.0 1964‑05‑13 4.5
1916‑05‑03 2.0 1968‑05‑11 2.7
1918‑04‑26 4.1 1982‑04‑30 2.8
1918‑05‑15 2.0 1992‑05‑12 9.4
1923‑05‑03 3.0 2001‑05‑04 3.2
1931‑05‑06 2.0 2001‑05‑05 2.9
1948‑04‑26 4.0 2002‑04‑25 2.0
1952‑05‑05 2.8 2002‑04‑26 4.4
1962‑05‑07 2.0 2008‑04‑30 3.4

It’s not all that frequent, with only 18 occurrences in the last 98 years, and two of those 18 coming two days in a row. The pattern is also curious, with several in the early 1900s, one or two in each decade until the 2000s when there were several events.

In any case, I’m not looking forward to it. We’ve still got a lot of hardpack on the road from the 5+ inches we got a couple weeks ago and I’ve just started riding my bicycle to work every day. If we do get 2 inches of snow, that’ll slow breakup even more, and mess up the shoulders of the road for a few days.

tags: snow  weather 
mon, 19-nov-2012, 19:55
Footprints frozen in the Creek

Footprints frozen in the Creek

Reading today’s weather discussion from the Weather Service, they state:


The last time it snowed was November 11th, so if that does happen, it will be at least 15 days without snow. That seems unusual for Fairbanks, so I checked it out.

Finding the lengths of consecutive events is something I’ve wondered how to do in SQL for some time, but it’s not all that difficult if you can get a listing of just the dates where the event (snowfall) happens. Once you’ve got that listing, you can use window functions to calculate the intervals between dates (rows), eliminate those that don’t matter, and rank them.

For this exercise, I’m looking for days with more than 0.1 inches of snow where the maximum temperature was below 10°C. And I exclude any interval where the end date is after March. Without this exclusion I’d get a bunch of really long intervals between the last snowfall of the year, and the first from the next year.

Here’s the SQL (somewhat simplified), using the GHCN-Daily database for the Fairbanks airport station:

    SELECT dte AS start,
        LEAD(dte) OVER (ORDER BY dte) AS end,
        LEAD(dte) OVER (ORDER BY dte) - dte AS interv
    FROM (
        SELECT dte
        FROM ghcnd_obs
        WHERE station_id = 'USW00026411'
            AND tmax < 10.0
            AND snow > 0
    ) AS foo
) AS bar
WHERE extract(month from foo.end) < 4
    AND interv > 6

Here’s the top-8 longest periods:

Start End Days
1952‑12‑01 1953‑01‑19 49
1978‑02‑08 1978‑03‑16 36
1968‑02‑23 1968‑03‑28 34
1969‑11‑30 1970‑01‑02 33
1959‑01‑02 1959‑02‑02 31
1979‑02‑01 1979‑03‑03 30
2011‑02‑26 2011‑03‑27 29
1950‑02‑02 1950‑03‑03 29

Kinda scary that there have been periods where no snow fell for more than a month!

Here’s how many times various snow-free periods longer than a week have come since 1948:

Days Count
7 39
10 32
9 30
8 23
12 17
11 17
13 12
18 10
15 8
14 8

We can add one more to the 8-day category as of midnight tonight.

tags: Fairbanks  snow  SQL  weather 
tue, 06-mar-2012, 18:44
Nika in a blizzard

Nika in a blizzard

This morning we had five inches of new snow on the ground, and it’s been snowing pretty consistently since, with really heavy snowfall in the last hour or so. As of midnight last night Fairbanks was 12.7 inches below normal for cumulative snowfall since July 1st (last year), but if this keeps up, we may actually get to the normal amount of snowfall. It’s been many years since that happened.

Unfortunately, like last year, the blizzard of 2012 is coming at the very end of the winter. Last year we got more than a foot of snow at the end of February, and this time around it’s even later. Still, there’s at least three more weeks of good ski conditions to look forward to, and this snow may help flatten some of the bumps on the Valley trail.

It’s hard to take a photograph that captures what a blizzard looks like because the snow that’s falling just mushes the background, but take my word for it: it’s really coming down!

tags: Nika  snow  weather 

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