gordon.dewis.ca - Random musings from Gordon


Archive for January 2012

Are Ottawa’s winters less snowy? It depends on how you look at it.

January 26, 2012 @ 21:12 By: gordon Category: Statistics, Weather

Charles over at Guide Gatineau posted an interesting article this morning looking at the implications of climate change on skiing and snowshoeing in the Ottawa area. He included a graph showing a the 30-year moving average of seasonal precipitation recorded at the Experimental Farm between 1890 and 2008. He asks “Do my eyes deceive me or does it look to you as if today we get only something over 1½ metres”, and based on the graph at first glance he’s not wrong — in the last few years we’ve averaged around 160cm of snow per winter.

Looking at the graph in question, it does appear that there has been less snowfall recorded at the Experimental Farm’s weather station recently compared to the start of the record, though the total annual precipitation, including both rain and snow, shows an upward trend over time. There are many factors that could be affecting the snowfall accumulation data. For example, over the years the Experimental Farm has gone from being in a rural setting to an urban setting by virtue of the fact that the city has grown around it. If the weather observation site had remained in a rural environment, the snowfall record might be quite different. Trees and buildings around the Farm have gotten bigger over the years, which probably has had an impact on the wind patterns at the Farm. This could result in less drifting snow, which could result in less accumulation.

Another thing about the graph is that seasonal precipitation is reported in millimetres. Presumably, they’re using a 10:1 conversion factor for snow:water, though they could have melted a column of snow and recorded the actual amount of water — either method is fine for our purposes. The blue line represents January to March precipitation, most of which is probably snow, but could be rain or some other type of precipitation like hail. The brown line represents October to December and this is where things get a bit problematic because there’s a fair chance that precipitation in those months can be a mix of rain and snow. Without a distinction between rain and snow, we have no way of knowing how much snow we should be adding to the snow calculated from the blue line to get a reasonable estimate of the total snowfall. In other words, using just the blue line to calculate the amount of snow results in under estimation.

Intrigued by Charles’ graph, I decided to do my own analysis using monthly weather data from Environment Canada’s Climate Data website. The results are interesting and tell a slightly different story from the data in the graph from the Experimental Farm.


Capturing snowflakes (Part 1)

January 20, 2012 @ 00:47 By: gordon Category: General, Weather

Regular viewers of The Big Bang Theory will recall the episode in which Leonard gave Penny a snowflake from the North Pole that he had preserved on a piece of glass using cyanoacrylate glue (CA), aka Krazy Glue. Figuring that it was likely possible, like most of the science and geeky things on the show, I turned to Google to find out how it’s done.

It turns out that it’s fairly straight forward, at least in theory.



January 17, 2012 @ 10:16 By: gordon Category: Out and about, Photography, Weather

It was snowing on the way to work today. I noticed one really nice snowflake that landed on my glove so I tried taking a picture of it.

It’s a bit overexposed, but given that I shot it with my point-and-shoot in macro mode hand holding it while waiting for the light to change it’s not too bad. It looks like a stellar dendrite with a bit of rime on it.


Friday’s weather pictures

January 13, 2012 @ 14:21 By: gordon Category: Photography, Weather

The first shot is Holland north of Wellington at lunch and the second is from my office window this morning…

This is probably going to suck

January 13, 2012 @ 08:59 By: gordon Category: Weather

I just took a look at the radar and this is probably going to suck:


Yup… (FZRA is freezing rain and FZDZ is freezing drizzle)

TAF CYOW 131138Z 1312/1412 04008KT 5SM -FZRA BR OVC006 TEMPO
1312/1314 2SM -FZDZ BR OVC003
FM131500 03006KT 2SM -SN SCT006 OVC012 TEMPO 1315/1321 1/2SM SN
BECMG 1316/1318 33010KT
FM132100 31018G28KT 3/4SM -SN BLSN OVC012 TEMPO 1321/1324 3SM -SN
FM140000 29015G25KT 11/2SM BLSN OVC020 TEMPO 1400/1404 P6SM NSW
FM140400 30015KT P6SM OVC030
FM141000 32010KT P6SM FEW020 BKN200

Extra special weather today, eh?

January 12, 2012 @ 23:00 By: gordon Category: Weather

So, we had some special weather in Ottawa today:

METAR CYOW 130200Z 08015G23KT 4SM -FZDZ -SN SCT006 OVC020 M05/M06 A2942 RMK SF4SC4 SLP970=
SPECI CYOW 130146Z 08017G22KT 6SM -FZDZ -SN SCT007 OVC018 M05/M06 A2942 RMK SF3SC5 SLP971=
SPECI CYOW 130131Z 08018KT 6SM -SN -PL DRSN SCT007 OVC018 M05/M06 A2943 RMK SF3SC5 SLP973=
METAR CYOW 130100Z 08017G25KT 8SM -SN DRSN FEW007 OVC022 M05/M06 A2944 RMK SF2SC6 SLP976=
SPECI CYOW 130024Z 08016G23KT 3SM -SN BR DRSN FEW008 OVC025 M05/M06 A2946 RMK SF2SC6 SLP982=
SPECI CYOW 130018Z 08018G24KT 1SM -SN BR DRSN VV005 M05/M06 A2946 RMK SLP983=

Translation: Freezing ick with wind.

And it looks like there’s more delightful weather in store for the next day or so:

TAF CYOW 130238Z 1303/1324 08012G22KT 6SM -FZDZ BR SCT008 OVC020
TEMPO 1303/1309 3SM -SN BKN008 OVC020
BECMG 1304/1306 07010KT
FM130900 07007KT 2SM -FZRA BR OVC005
FM131400 36005KT 2SM -SN SCT006 OVC012
FM131600 33007KT 1/2SM SN VV005
FM132100 31015G25KT 2SM -SN BLSN OVC012

Translation: Freezing ick with wind overnight, followed by some freezing ick and snow during the day tomorrow. And then more wind.

Fun stuff.

Dark Matter #1: A review

January 11, 2012 @ 14:25 By: gordon Category: Comic books, Reviews

It’s Wednesday and that means it’s new comic day. And today it also means that it’s Dark Matter #1 release day, which regular readers will remember me writing about in the past. Accordingly, I headed out to Silver Snail at lunch and picked up the disturbingly large pile of comics waiting for me. I got back to the office in time to read Dark Matter #1 before having to head to a meeting, so I thought I’d post a quick review.