Vancouver Cold Snap Rating Scale

[Typeing3]

Typeing3's Vancouver Cold Snap Rating Scale

Category 1 - The Arctic Fart
Highs: 2c to 0c
Lows: -2c to -6c

Category 2 - The Modified Arctic Blast
Highs: 0c to -2c
Lows: -6c to -10c

Category 3 - The Respectable Arctic Blast
Highs: -2c to -4.5c
Lows: -10c to -12.5c

Category 4 - The Classic Arctic Blast
Highs: -4.5c to -7c
Lows: -12.5c to -15c

Category 5 - The Extreme Arctic Blast
Highs: Below -7c
Lows: Below -15c



Note: Calculated using the average high and low over the coldest three-day stretch of any cold snap.

[SouthSardiswx]

good one Tman how about one more.
Category 0 - The Arctic Anus
Highs: 2c to 5c
Dewpoint: -18c

[VanCitySouth]

I was thinking there should be a multi-criteria winter rating scale

Criteria could include:

• Temperature (extreme minimum, low maximum)

• Snowfall (overall total, maximum single-storm total, maximum snow cover)

• Duration of cold (how many days sub-freezing/lows below -10, length of snow cover, number of distinct cold snaps)

• Extra factors (did the arctic front bring snow, were the snowfalls daytime or nighttime, how was the transition out)

[Abby_wx]

I have troubling viewing December's event as a true Cat 5. The thresholds were barely met and were only sustained for one day. It's a solid Cat 4 for me. A true Cat 5 would be January 1950, December 1968 or similar to those -- basically a couple times in a century type of events.

[Typeing3]

I have troubling viewing December's event as a true Cat 5. The thresholds were barely met and were only sustained for one day. It's a solid Cat 4 for me. A true Cat 5 would be January 1950, December 1968 or similar to those -- basically a couple times in a century type of events.

Duration is an extra variable that definitely should be incorporated into the rating scale for cold snaps.

There could even be a completely different rating scale for an entire month, with contributing variables including the monthly average temp and a few others like extreme low.

[Typeing3]

For example, the late December 2021 cold snap would be a category 4 cold snap.

Coldest three-day stretch at YVR (high/low)

Dec 26: -5.7c/-10.8c
Dec 27: -7.8c/15.3c
Dec 28: -4.4c/-12.8c

Average high/low over three days: -6.0c/-13.0c = category 4 cold snap.

[Glacier]

Three coldest days on record at YVR based on hourly data (since 1953):

1) Dec 29, 1968 = -14.93 C
1) Dec 28, 1968 = -14.93
3) Dec 16, 1964 = -13.57

Coldest 5 3 day stretch on record based on hourly data (since 1953)... I went 5 to get a 3-day stretch that wasn't in the winter of 1968/69.
1) Dec 28-30, 1968 = -13.7
2) Dec 27-29, 1968 = -12.27666667
3) Dec 29-31, 1968 = -10.94666667
4) Jan 27-29, 1969 = -10.25666667
5) Nov 26-28, 1985 = -10.24333333

Coldest days on record based on Tmax (since 1937):
1) Dec 29, 1968 = -11.1
1) Jan 13, 1950 = -11.1
3) Dec 28, 1968 = -10.6
3) Jan 14, 1950 = -10.6
3) Jan 24, 1950 = -10.6
6) Dec 16, 1964 = -10
6) Jan 21, 1943 = -10

Coldest 3 days on record based on Tmax (since 1937):
1) Dec 28-30, 1968 = -10.2
2) Jan 13-15, 1950 = -9.833333333
3) Jan 12-14, 1950 = -9.466666667

Coldest days on record based on Tmin (since 1937):
1) Dec 29, 1968 = -17.8
1) Jan 14, 1950 = -17.8
3) Dec 16, 1964 = -16.7
3) Jan 14, 1950 = -16.7

Coldest 3 days on record based on Tmin (since 1937):
1) Dec 28-30, 1968 = -16.66666667
2) Jan 13-15, 1950 = -15.73333333
3) Jan 30-Feb 1, 1950 = -15.56666667
4) Jan 21-23, 1943 = -15.2

ALL CATEGORY 5s at YVR:
1) Dec 30, 1968 (end date of 3 day averages meeting threshold)
2)Jan 18, 16, & 15, 1950
3) Jan 23, 1943

ALL CATEGORY 4s at YVR:
1) Dec 29, 28, 2021
2) Nov 29, 1985
3) Jan 30, 29, 28, & 24, 1969
4) Dec 18, 1964
5) Jan 31, 28, 27, 19, & 4, 1950

ALL CATEGORY 3 winters at YVR:
1) Dec 2021
2) Dec 2008
3) Nov 2006
4) Jan 2004
5) Dec 1996

6) Jan 1996
7) Jan 1993
8) Dec 1990
9) Feb 1989
10) Nov 1985

11) Dec 1983
12) Jan 1982
13) Jan 1979
14) Dec 1978
15) Jan 1969

16) Dec 1968
17) Jan 1959
18) Jan 1957
19) Nov 1955
20) Jan 1954

21) Jan 1950
21) Jan 1943

Most recent CATEGORY 2: Jan 1, 2022

Most recent CATEGORY 1: Dec 1, 2022

All winters with no rated coldsnaps (since 1937):
2015/16

2007/08
2005/06
2002/03

1997/98
1994/95
1993/94
1991/92

1988/89
1982/83

1976/77

1966/67
1963/64
1960/61

1957/58
1952/53

1947/48
1945/46

1939/40
1938/39

So only the 1970s and 2010s had cold snaps 9 of 10 years.

[Typeing3]

Three coldest days on record at YVR based on hourly data (since 1953):

Wow, massive props to you for compiling this.

Thanks!


Rating scale seems to be fairly representative of the severity of each cold snap... three cat 5's (1943, 1950, 1968) over the period of record at YVR seems about right.

[Glacier]

funny, metro Vancouver hit -20 or colder in 4 different winters, but none of them were 1949/50!

Well, way up on Coquitlam Lake did, but that's into the mountains and a lot colder than where anyone lives.

LOWMLSOUTHEXLOW.png

[Typeing3]

funny, metro Vancouver hit -20 or colder in 4 different winters, but none of them were 1949/50!

Well, way up on Coquitlam Lake did, but that's into the mountains and a lot colder than where anyone lives.

LOWMLSOUTHEXLOW.png

You forgot -23.3c in Pitt Meadows (Pitt Polder station) in January 1969! Coldest temp on record in Metro Vancouver I believe.

Edit:
Nevermind, your map title is Metro Vancouver South.

[Glacier]

Just west of Pitt Polder... shockingly nothing from 1950!

VANXLOWS.png

EDIT: Oh, wow, not a single weather station in existence in the city of Vancouver 1950! The only ones north of Fraser were New West Minster (colder in 1875, Gibsons, and Coquitlam Lake (both colder in 1968).

1950lows.png

[Typeing3]

Just west of Pitt Polder... shockingly nothing from 1950!

VANXLOWS.png

EDIT: Oh, wow, not a single weather station in existence in the city of Vancouver 1950! The only ones north of Fraser were New West Minster (colder in 1875, Gibsons, and Coquitlam Lake (both colder in 1968).

1950lows.png

Wish the New Westminster station didn't close down since records began there in 1874. Would've been a great long term station for Metro Vancouver, given it's central location.

At least Agassiz is still (somewhat) there today with records back to 1889.

[Glacier]

Wish the New Westminster station didn't close down since records began there in 1874. Would've been a great long term station for Metro Vancouver, given it's central location.

At least Agassiz is still (somewhat) there today with records back to 1889.

1875 was the coldest year on record globally, and BC probably had its coldest and possibly coldest winter then. We will never know though because only 3 weather stations existed in the entire province: New Westminster, Esquimalt, and Spences Bridge. No station existed in Alberta, Saskatchewan, Yukon, NWT, or Nunavut so most of Canada had no weather monitoring.

So lots of margin of error on the global front due to so few stations, but still, a good bet for the coldest year on record...

globaltempsxx2.png

[Typeing3]

1875 was the coldest year on record globally, and BC probably had its coldest and possibly coldest winter then. We will never know though because only 3 weather stations existed in the entire province: New Westminster, Esquimalt, and Spences Bridge. No station existed in Alberta, Saskatchewan, Yukon, NWT, or Nunavut so most of Canada had no weather monitoring.

So lots of margin of error on the global front dew to so few stations, but still, a good bet for the coldest year on record...

globaltempsxx2.png

Pre-EC records exist too. 1861-62 was likely the coldest winter on record in BC. If not province wide, then I'd definitely say the south coast at least, as the Fraser River was frozen solid out to Richmond from January through March.