Deepfreeze: January 2020!

It is finally over, and so now let's take a look back at the great deepfreeze of January 2020.

If you are viewing this in the future all of the dashboards will include post-2020 data as well. So they will show the deepfreeze of 2020, plus any deepfreezes which may have come after it. If you want to see the charts as they looked originally, those are all in this twitter thread (assuming that twitter still exists in the future).

Today we will be talking about the deepfreeze of January 2020, and we will see that it set a lot of coldest-in-X-years records. But before we get to that it is important to mention that less than one year ago we also had the great deepfreeze of February 2019.


February 2019

We talked about the deepfreeze of 2019 in detail here, and it had its own set of coldest-in-X-years records:

• 9 Lows in-a-row of -25°C or colder: the most since 1996.
• 18 Lows in-a-row of -20°C or colder: the most since 1996 again.
• 11 Highs in-a-row of -15°C or colder: the most since 1998.
• 18 Highs in-a-row of -10°C or colder: the most since 1996 again.

Overall February 2019 ended up being our 5th coldest February since 1880, and our most below-average month since February 1979.

So during the 12 months from February 2019 to January 2020 we had two, separate coldest-in-a-generation (or two generations) deepfreezes. 

And now...

January 2020

The deepfreeze of February 2019 was very long, but the deepfreeze of January 2020 was very cold.


-37.6°C!

Probably the biggest shock of the January 2020 deepfreeze was that Blatchford had a low of -37.6°C on January 15th.

The last time that we hit -37°C had been 8,761 days earlier on January 19, 1996 at -37.8°C. And prior to that Blatchford's last -37°C had been 8,757 days earlier on January 27th, 1972. That January 1972 deepfreeze was also that last time that Blatchford hit -40°C, with a Low of -41.1°C on January 26th, 1972.

This also ended our streak of Lows above -35°C at 3,684 days. The last time we had hit -35°C was December 13, 2009 at -36.7°C. That had been the longest the we had gone without a -35°C, and the 2nd longest was 2,556 days from 1997 to 2004.

January 15th, 2020's Low of -37.6°C was only our *5th* coldest January 15th: 1896 hit -43.9°C, 1950 hit -40°C, and 1907 & 1930 hit -38.3°C.

And the High of -27.5°C was our 6th coldest, with the record of -33.3°C in 1896.

As is usually the case, Blatchford was the warmest location in the Edmonton region, with many of the surrounding stations about 5°C colder, and the International airport reaching -42.3°C. A 5°C difference is actually fairly small, because often on very cold days there will be an 8°C or 10°C difference between the city and the airport.


Lows of -30°C: 4 in-a-row

January 15th's -37.6°C was the coldest that we got, and was also the only day to hit -35°C. But we still had 4 Lows of -30°C in-a-row, with January 13th at -31.3°C, the 14th at -34°C, the 15th at -37.6°C, and the 16th at -30.7°C.

4 Lows of -30°C in-a-row made that Edmonton's 62nd longest streak. In "recent" memory 1997, 1996, 1989 & 1982 also all had 4 day streaks. Going a bit further back 1980 & 1977 both went 6 days. And the big standouts were 1954 with 14 days, 1893 with 13, and 1887 with 16.

So we hadn't seen one of these in 22 years, and before that they used to be quite a bit more common.

This chart shows when throughout the year we get our Lows of -30°C.

In recent years our -30°C Lows have stretched from as early as December 6th in 2013, to as late as March 10th in 2009. January has had the most with 18, followed by December with 9, February with 6 (even though people are always hating on February), and then March with 4.

Looking back through history to the 1880s the range for -30°C Lows stretched all the way to early November, although late-January has been when they have most frequently arrived.

In the 21 years since 2000 Blatchford has only recorded 37 Lows of -30°C. In the 10 years from 1990-1999 there were 42, and going further back the 1960s had 82, the 1930s had 124, and etc.


Lows of -25°C: 7 in-a-row

For Lows of -25°C in-a-row this deepfreeze went 7, from January 12th through 18th.

That was 2 days less than the 9 days in-a-row in February 2019. But other than 2019, this was the longest streak since 1996 with 12 days.

Prior to the 1980s 10 Lows in-a-row of -25°C were quite common, happening 30 times from 1880-1980. The longest streak was 26 days during the infamous deepfreeze of January 1969.

So we saw one of these last year, but prior to that it had been 22 years.


Lows of -20°C: 11 in-a-row

For Lows of -20°C we went 11 in-a-row, which was well below the 18 in February 2019. In recent years we had gone also 9 days in 2018, 2011, and twice in 2008.


Highs of -30°C: None (just barely)

Our coldest High of this deepfreeze was -29.7°C on January 14th. While that is really, really close to -30°C, we didn't technically have any Highs of -30°C.

The longest recorded period without a High of -30°C was 6,215 days from January 26, 1972 to January 31st, 1989. As I write this in January 2020 we are in the 2nd longest streak at 5,840ish days, going back to January 27, 2004.

January 14th, 2020 did end our streak of days without a High of -29°C at 5,830 days (going back to January 27, 2004 again). The 2nd longest streak without a -29°C was 3,979 days from 1954 to 1964.


Highs of -25°C: 4 in-a-row

We had 4 Highs in-a-row of -25°C or colder.

In recent years 2004, 1997, 1989, 1984 & 1982 were all just below that at 3. To find a year with more than 2020 we need to go back to 1980 & 1977 which both went 5 days. The record was 1936 with 14.


Highs of -20°C: 6 in-a-row

And finally, we had 6 days with Highs of -20°C or colder, from January 12th to the 17th.

That was the most since 1998 which had 12, and the big standout is once again January 1969 with 26. In recent years 2004 had also gone 6, and 2011 & 2003 went 5.


Calgary

Calgary was also hit with this deepfreeze, although it was not quite as severe as in Edmonton:

• Calgary's lowest temperature was only -32.4°C on January 15th.
• They had 3 -30°C Lows, 7 -25°C Lows, and 11 -20°C Lows in-a-row.
• They had 4 -25°C  Highs, and 4 -20°C Highs in-a-row.

All of the dashboards here also include the data for Calgary, and that can be selected using from the dropdown on the upper-right. The data for Regina and Winnipeg is also there, and they also had a few cold days, but Alberta really got the worst of it.


Recent Deepfreezes

This chart is not my favourite, because it can get incredibly messy incredibly quickly. But here it is set to show the temperatures for streaks of 11 or more Lows of -20°C in-a-row. So 2020 is here with 11, and 2019 has 18. There are a few 13s and 15s in the 1990s, and the big one was 23 days in February 1996.

The rainbow dots in the lower portion of the dashboard show all of the 11-day streaks going back to 1880. Prior to 2000 things like this happened quite frequently, but then there is the big gap between 1997 & 2019 because these just are not very common anymore.

On this dashboard you can change the temperature ranges to see how January 2020 lined up with other deepfreezes, but again, the chart gets very busy very fast.


Overall

This chart is also a little messy, but it shows the average Low temperatures for each January & February going back to 1881.

The deepfreeze of February 2019 was so long that it made February 2019 our 5th coldest February overall. The deepfreeze of January 2020 was colder but also shorter, and so as I write this at the end of the deepfreeze it is only roughly our 30th coldest January. And with a warm week ahead that will likely change by the end of the month.


Summary:

We've had two first-time-in-a-generation deepfreezes within the past 12 months. February 2019 was long, and January 2020 was cold.

January 2020 notables:

• The first Low of -37°C since 1996, and the first -35°C since 2009.
• 4 Lows of -30°C in-a-row, which was the most since 1997.
• 7 Lows of -25°C in-a-row, which was the most since 1996, except for the 9 in 2019.
• 11 Lows of -20°C in-a-row, which was the most since 1998, except for the 18 in 2019.
• The first High of -29°C since 2004.
• 4 Highs of -25°C in-a-row, which was the most since 1980.
• 6 Highs of -20°C in-a-row, which was the most since 2004.

February 2019 notables:

• The most -25°C Lows (9) & -20°C Lows (18) in-a-row since 1996.
• The most -15°C Highs (11) & -10°C Highs (18) since the mid-late 1990s
• It was the coldest month since January 1982, and the coldest February since 1979.

Looking at all of the charts today there are big gaps between these two most recent deepfreezes and the previous ones in the mid-1990s, or the early-1980s. In recent years we had not seen these types of extended cold temperatures, but prior to 1980 these deepfreezes would not have been particularly unusual.