Final Weather Blog

Whistler British Columbia experiences numerous climate controls on both a macro and micro scale.  The Koppen-Geiger climate classification system categorizes it as a Dsb climate.  D climates are commonly found between latitudes of 40–60°N and S.  Whistler resides at 50.12°N.  This classification also means Whistler experiences temperatures above 10°C during the warmest months and below −3°C during the coldest months, the warmest month averaging below 22°C along with dry summers and wet winters.  

Image from: "Climate & Weather." Destination British Columbia. N.p., n.d. Web. 12 Mar. 2014.

Whistler is located continentally in the Canadian Rocky mountains, but is close enough to the pacific coastline to see strong affects from maritime air masses.  This orographic feature dictates much of the areas climate.  The mountains lift incoming air masses arriving from the Pacific Ocean,  causing most of Whistler's precipitation which during wet winter months typically falls as snow.  Whistler's altitude of 7,156 feet also means cooler year round temperatures and higher exposure to sunlight.  The mountains and large amounts of snow have also created a micro scale control.  Whistler has become an extremely popular ski town, bringing in tourists from around the globe to ski amazing features and heavy powder.  The resort and logging industries in the area have cut down vegetation in order to sustain the attraction.  Along with tourism and a population increase comes an increase in pollution and human traffic.  This may be a factor in the average temperatures of the area becoming more extreme over the past 50 years.  Winter temperatures have dropped slightly, and average summer temperatures have risen by almost 10°F. 

Images from: "Meso & Microclimates of British Columbia." Weather and Climate of British Columbia Canada. N.p., 2 May 2012. Web. 09 May 2014.

Trends in yearly average temperature have risen steadily in the past 50 years.  They seem to follow the same pattern as Whistler's population increases with spikes in warm temperatures since the early 1980's.  According to Whistler 2020 the average yearly temperature rose from 5.2°C to 8°C since the late 1970's which is when skiing and the Whistler Blackcomb Ski Resort started to gain mass popularity.  This hints at the creation of a possible seasonal urban heat island, with the rise of human population during winter months and fall during summer months.

Whistler BC average temperature history

Image from: "Climate Trends and Variations Bulletin - Annual 2013." Government of Canada, Environment Canada. N.p., n.d. Web. 09 May 2014. 

Historical population
Year	Pop.	±%
1981	1,369	—
1986	2,002	+46.2%
1991	4,459	+122.7%
1996	7,172	+60.8%
2001	8,896	+24.0%
2006	9,248	+4.0%
2011	9,824	+6.2%

Image from: "Whistler, British Columbia." Wikipedia. Wikimedia Foundation, 05 July 2014. Web. 09 May 2014.

Whistler British Columbia's climate is similar to that of San Francisco.  They both reside near the pacific coast of their countries and thus have similar precipitation patterns.  Moist are moving in from the ocean causes a winter wet season, and continental air masses cause drier summers for both locations. San Francisco's close proximity to the ocean and the fact that it is surrounded on three sides by water mean it experiences more moisture, and also more moderate temperatures.  Whistler is also at a higher altitude which results in cooler temperatures in general.  The mechanisms for precipitation vary in these locations.  While Whistler has storms caused by its orographic features uplifting moist air, San Francisco's precipitation is caused mostly by mid latitude cyclones that create occluded fronts.  

San Francisco Climate Graph

Image from: "Weather & Climate: An Analysis of San Francisco." Weather & Climate: An Analysis of San Francisco. N.p., n.d. Web. 09 May 2014. 

References:

"Climate & Weather." Destination British Columbia. N.p., n.d. Web. 12 Mar. 2014.

"Climate Trends and Variations Bulletin - Annual 2013." Government of Canada, Environment Canada. N.p., n.d. Web. 09 May 2014. <http://www.ec.gc.ca/adsc-cmda/default.asp?lang=En&n=8C7AB86B-1>.

"Environment, Land and Resource Use." Whistler2020 -. N.p., n.d. Web. 09 May 2014. <http://www.whistler2020.ca/whistler/site/genericPage.acds?instanceid=2986153&context=2985223>.

"Meso & Microclimates of British Columbia." Weather and Climate of British Columbia Canada. N.p., 2 May 2012. Web. 09 May 2014. <http://climatebc.wordpress.com/2012/05/02/meso-microclimates-of-british-columbia/>.

"Weather & Climate: An Analysis of San Francisco." Weather & Climate: An Analysis of San Francisco. N.p., n.d. Web. 09 May 2014. <http://weatherclimateananalysisofsan.blogspot.com/>.

"Whistler, British Columbia." Wikipedia. Wikimedia Foundation, 05 July 2014. Web. 09 May 2014. <http://en.wikipedia.org/wiki/Whistler%2C_British_Columbia>.

Section III Weather Blog

Whistler British Columbia is affected mainly by three air masses.  These are the maritime polar air mass (mP), arctic air mass (A), and continental polar air mass (cP).  To a lesser extent, the maritime tropical air mass (mT) will move further north and affect Whistler's climate.  Maritime air masses tend to have more influence in British Columbia during the winter months than in the summer.  

Air masses and Polar front affecting Whistler BC

Image from: National Weather Service. N.p., n.d. Web. 13 Apr. 2014. 

The cities location at about 50 degrees north means it does not experience many mid latitude cyclones.  It is just above the polar front, so although plenty of these cyclones develop around the area they move southwest before any impact is created.  When there is an affect from these cyclones, they create occluded fronts.  Warm occlusions in the summer, and cold occlusions during the winter season.  

Whistler falls into a long wave ridge which typically sees the arrival of high pressure systems that rotate clockwise. This is caused by convergence in the troposphere and divergence at the surface making air parcels sink.  With low pressure systems surrounding it, warm occluded fronts form that bring precipitation to the region.

The area is currently experiencing an occluded front that is viewable in the image below moving down towards the pacific northwest of the United States in the following days.  This front has brought and should continue to bring small chances of light precipitation through Wednesday April 16.  

Weather forecast map for Canada April 15 and 16

Image from: "Weather at a Glance." Environment Canada. N.p., n.d. Web. 14 Apr. 2014. 

A large factor in Whistler's weather and climate lies in its topography.  The city is located centrally in the Canadian Rocky Mountains which run north to south.  The orographic feature lifts the air masses that approach it, creating clouds.  With the maritime polar air mass constantly moving westward towards the mountains, a large amount of vapor is lifted.  This is a key component in the vast amounts of snowfall the area receives.

Every so often a deep column of moisture known as the pineapple express moves northwest from the pacific ocean around Hawaii up towards the west coast of North America.  The maritime tropical air mass and a branch of the polar jetstream carries this vapor concentrated air inland causing massive amounts of precipitation.   Below is an image of the pineapple express reaching the mainland in January of 2009.  This "atmospheric river" reached far enough North to affect Whistler and brought generous snowfall.

Pineapple Express moving far enough north to affect Whistler BC

Image from: "COPE Laboratory - Research Projects." COPElab School of Resource and Environmental Management RSS. N.p., n.d. Web. 13 Apr. 2014. 

References:

"Air Flow Through Two Wintertime Mid-Latitude Cyclones Interacting with Mountains." Air Flow Through Two Wintertime Mid-Latitude Cyclones Interacting with Mountains. N.p., n.d. Web. 13 Apr. 2014. <http://adsabs.harvard.edu/abs/2011AGUFM.A51C..05B>.

"COPE Laboratory - Research Projects." COPElab School of Resource and Environmental Management RSS. N.p., n.d. Web. 13 Apr. 2014. <http://www.rem.sfu.ca/COPElab/research/research-projects/>.

National Weather Service. N.p., n.d. Web. 13 Apr. 2014. <http://www.srh.weather.gov/srh/jetstream/synoptic/images/airmasses.gif>.

"THE PINEAPPLE EXPRESS." THE PINEAPPLE EXPRESS. N.p., n.d. Web. 14 Apr. 2014. <http://www.weather.com/blog/weather/8_10838.html>.

"Pineapple Express." Wikipedia. Wikimedia Foundation, 14 Apr. 2014. Web. 14 Apr. 2014. <http://en.wikipedia.org/wiki/Pineapple_Express>.

"Weather and Climate of British Columbia, Canada." Weather and Climate of British Columbia Canada. N.p., n.d. Web. 13 Apr. 2014. <http://climatebc.wordpress.com/>.

"Weather at a Glance." Environment Canada. N.p., n.d. Web. 14 Apr. 2014. <http://weather.gc.ca/jet_stream/index_e.html>.

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Section II Weather Blog

Whistler, British Columbia's climate is governed by its close proximity to the Pacific coastline as well as its location in the Rocky Mountains.  The oceanicity of the city beacons moderate year round temperatures. The climate is affected mostly by the maritime polar air mass and continental polar air mass, but the maritime tropical air mass is also a factor.  The movement of these masses along the mountains determines which areas of British Columbia receive moisture and which remain dry.  During winter months, rainfall is still common in lower elevations while the higher peaks see large amounts of snowfall.  Snowfall continues into May due to the cooling of air moving in from the Pacific Ocean.  Even during the summer, high pressure systems moving in from the coastline create cooler nighttime temperatures.  Extreme weather conditions are common between November, which is there wettest month, and February.  When temperature decreases, the maximum amount of water vapor the atmosphere can hold also decreases. The moderate temperatures of Whistler create the perfect climate for larger amounts of water vapor in the air during winter seasons.  This wet coastal air coupled with high pressure systems moving in from the Pacific that lift the saturation create generous and frequent snow storms.
Since the climate is affected by two maritime air masses that move in from the Pacific Ocean The latent heat flux should be higher than the sensible heat flux for most of the year due to the larger amount of water vapor in the air.  For this reason I would estimate the Bowen Ratio to be around 0.55 during the moist winter season and 0.65 to 0.7 during the drier summer months.

Table 1: Average Monthly Temperatures

Month	Daily Highs	Daily Lows
January	-0.6°C , 33.1°F	-4.9°C , 23.2°F
February	3.2°C , 37.8°F	-4.2°C , 24.4°F
March	7.2°C , 45°F	-2.3°C , 27.9°F
April	11.8°C , 53.2°F	0.3°C , 32.5°F
May	16.4°C , 61.5°F	3.8°C , 38.8°F
June	19.9°C , 67.8°F	7.2°C , 45°F
July	23.6°C , 74.5°F	9.2°C , 48.6°F
August	24°C , 75.2°F	8.9°C , 48°F
September	19.8°C , 67.6°F	5.6°C , 42.1°F
October	11.2°C , 52.2°F	2°C , 35.6°F
November	3.5°C , 38.3°F	-1.8°C , 28.8°F
December	-0.2°C , 31.6°F	-5.4°C , 22.3°F

Table 2: Average Monthly Precipitation (Rainfall and Snowfall Included)

Month	Precipitation	Rainfall	Snowfall
January	157.2 mm	68.9 mm	96.3 cm
February	119.5 mm	60.3 mm	66.8 cm
March	96.1 mm	54 mm	45.5 cm
April	75 mm	59.3 mm	16.6 cm
May	66.2 mm	65.1 mm	1.1 cm
June	58.1 mm	58.1 mm	0 cm
July	47.7 mm	47.7 mm	0 cm
August	47.5 mm	47.5 mm	0 cm
September	63.7 mm	63.7 mm	0 cm
October	147.4 mm	138.3 mm	8.8 cm
November	188.2 mm	126.5 mm	64.9 cm
December	162.3 mm	60.6 mm	111.2 cm

Image from: "Climate & Weather." Destination British Columbia. N.p., n.d. Web. 12 Mar. 2014.

References:

"Climate & Weather." Destination British Columbia. N.p., n.d. Web. 12 Mar. 2014.

"The Mountains." Whistler Blackcomb. N.p., n.d. Web. 12 Mar. 2014.

"Weather and Climate of British Columbia, Canada." Weather and Climate of British Columbia Canada. N.p., n.d. Web. 12 Mar. 2014.

"Whistler British Columbia Canada Climate Graphs, with Monthly Temperatures, Precipitation, & Snowfall in Whistler." Whistler British Columbia Canada Climate Graphs, with Monthly Temperatures, Precipitation, & Snowfall in Whistler. N.p., n.d. Web. 12 Mar. 2014.

"Whistler, British Columbia." Wikipedia. Wikimedia Foundation, 03 Nov. 2014. Web. 12 Mar. 2014.

"Whistler Monthly Climate Average, Canada." Whistler, Canada Weather Averages. N.p., n.d. Web. 12 Mar. 2014.

"Whistler Weather History & Stats." Whistler Photo. N.p., n.d. Web. 12 Mar. 2014.