wind chill

Just in case you're wondering how wind chill works...

(This is a repost from January 2008.)

If you live somewhere in Canada, the northern US, or anywhere there are frigid temperatures you're probably aware of something called wind chill. This is the colder temperature the weatherman will give when he tells you how cold it feels versus the actual thermometer reading.

The idea of wind chill has interested me ever since I heard about it as a kid. And so in keeping with the blogland focus on weather this January (thanks to Rebecca Writes, who lives in the Yukon, where wind chill is a big deal), I thought I'd check it out for myself. Here are some things I discovered.

A layer of warm air up to several millimeters thick surrounds human skin. In exposed skin wind thins that layer. The stronger the wind, the thinner the insulating layer of warmth guarding the skin.

We humans don't sense the temperature of the air, but the temperature of our skin. When the wind robs our skin of its layer of insulation it feels closer to the temperature of the air. That's why exposed skin feels colder on a windy day than a calm one and we experience the phenomenon called wind chill.

Wind chill is calculated by a complicated formula. It takes into consideration engineering correlations of wind speed and heat transfer rate, and used to be expressed in 1000 - 3000+ watts per square meter. But how cold is 1500 watts per square meter? In order to make the wind chill number meaningful, scientists found a way to convert it into an equivalent temperature.

Thus you'll hear your weatherman say something like, "Bundle up. It's -10 but the wind chill factor will make it feel more like -21" This simply means that your face when exposed to the 40 km/hr wind that is predicted along with the -10C temperature will feel like it would on a day when the temperature is -21C with no wind.

Well, not exactly no wind. The lowest measure on an anemometer is a wind of 5 km/hr and also factored into the calculation is the assumption that you are walking (into the wind) at 3 km. per hour.

Some wind chill facts:

*Wind chill doesn't affect objects to make them freeze. If, for example, the wind chill factor is -4C (25F), water will not freeze if the air temperature is 2C (35F).

*Wind chill controversies: Should the method for calculating wind chill be based on:
- whole body cooling while naked
- or whole body cooling while wearing appropriate clothing
- or on cooling of the most exposed skin, such as the face?

*The coldest wind chill in Canada was at Pelly Bay Nunavut, January 13, 1975 when 56 km/hr winds made the temperature of -51C feel like -92C (3,357 watts per square meter).

*Wind chill impacts life in many ways, as in deciding what to wear when going outdoors and whether kids get to play outside at recess.

*Frostbite comes as a result of skin freezing. Symptoms: swelling, redness, tingling, burning --> white and waxy skin --> infection and loss of extremities.

*Hypothermia happens when body temperature falls below 35C (normal is 37C). Symptoms: drowsiness, bad coordination, weakness.

*This wind calculation chart also gives frostbite risk. (The chart is from Environment Canada.)

*If you know the temperature and wind speed, you can calculate the wind chill where you live. (This is an English system calculator. For those using metric - here are links to conversion tables: Km. to miles & celsius to fahrenheit).

fat river

The Fraser River is high with the spring melt. We walked through the Derby Reach campsite yesterday. Many campsites are occupied - not by campers but water.





The campers who were there didn't seem the least bit concerned, though. I suppose the rise in the river is altogether predictable so if there were danger of even higher water, there would be lots of time to get away.


We walked the Edgewater Bar Trail to Derby, the first Fort Langley. In one place the water was about to nibble at our toes.


For comparison of how much the river has risen, this photo of the cutaway bank near the Derby heritage cairn was taken in January this year...


and this is what it looked like yesterday.

blogging the weather

We're having a stretch of stellar weather and here's proof.

The photo below was taken on Sunday (driving east on Highway 91, Burnaby highrises in the distance). Note the fresh snow on the mountains and the clear blue sky.



Monday was just as beautiful. And no matter which weather web site I consult, the forecast for Tuesday and Wednesday are just as grand. It's cold (for us) but the sunshine is so welcome!







For more blogland weather, see Rebecca Writes.

r.a.i.n.

r - regular
a - abiding
i - interminable, incessant
n - non-step, never-ending

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For more bloggy January weather, look here.

ice? nice!

One of the ways weather impacts our lives is how it determines what we do for recreation. As someone who grew up in Saskatchewan, it was natural for me to take for granted things like skating outdoors in the winter. But you certainly can't count on a winter skate on an outdoor pond in the more temperate lower mainland of British Columbia where I live now.

In this era of indoor rinks, the weather is no longer a factor for activities like hockey, figure skating and curling. However it still is for skiing, snow-boarding, snowshoeing, dog-sledding and - ice sculpting.

Last week I got an email with some pretty amazing photos of ice sculptures. These are from one of the biggest ice and snow sculpture competitions on the globe, Harbin China. You certainly need an outdoor deep freeze to keep these building-sized ice structures intact. But the results, especially with the reflection of all the lights at night, are stunning. Dates of this year's festival are right now - January 6-13








And did you know there were ice hotels? These are actually giant igloos, converted into destination hotels. They are usually built beside rivers or lakes from which the builders draw water, freeze it and cut the ice into large blocks before trucking it into place. A large hotel takes five to six weeks to build.

The original ICEHOTEL is in Jukkasjärvi, Sweden. From an article on How Stuff Works:

ICEHOTEL boasts unique rooms, a starkly beautiful church and the ABSOLUT ICEBAR, where the bar and the glasses are all made from ice. During the day, the hotel opens to visitors who tour the rooms without staying the night. But at 6 p.m., the ice museum closes and overnight guests take over. They leave their luggage with a porter, who takes it to a heated storage area. Bathrooms and changing rooms are also heated. By 9 p.m., most people retire to their rooms. Guests wear long underwear and sleep in mummy bags on ice blocks covered by mattresses and reindeer skins.
- read the rest

There is also an ice hotel in Quebec (Hotel de Glace Inc.). It is Located at the Station touristique Duchesnay on the shores of Lake St. Joseph and comes complete with a chapel for weddings. Check out these photos.

As for the weather here - today I woke up to snow. But it's currently raining. My town would be a heartbreak of a place for ice sculptors.

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To learn more about the weather all over blogland, go this post at Rebecca Writes.

web camboree

There's nothing like a web cam for snooping on weather almost anywhere. We usually check the web cams of these mountain passes before we make a trip to the interior.

Coquihalla Snowshed cam (elevation 980 meters)
Coquihalla Summit cam (elevation 1220 meters)
Brenda Mine cam - on the Okanagan Connector (elevation 1230 metres)

Of course, web cams are good for a lot more than checking on road conditions and weather. Cams set up at local spots of congestion - like ferries, bridges and border crossings help gauge the lineups so you can plan your trip.

This B.C. government page has links to web cams stationed on highways all around the province.

This Greater Vancouver Regional District (GVRD) page has links to the dozens of web cams around the lower mainland.



Today the weather where I live is cloudy and mild (9C). The proof is in the web cam shot I just snatched from the screen of the Langley Redwood Golf Course cam (the closest web cam to where I live). Click on the link during daylight hours for our current weather whenever you happen to be reading this.

Should you want to keep an eye on traffic in Croatia, watch Niagra Falls or check on the weather in Capetown, this earth cam page (five pages of links) will give you your fill of cams from all over the world.

They also have a list of the 25 most interesting web cams of 2007.

Now surf on over to Rebecca Writes, especially on any Tuesday and Friday in January to read about the weather in the rest of blogland. Rebecca is hosting a weather theme all month. Join in by posting something about the weather where you live, then go here to find out how to be part of Weather Reporting in blogland.