8:30a – Weather briefing · Review Saturday's 'Lessons'

9:00a – Lecture: Winter Climate and Snow Processes– Mountain winter climates (light, thermal, moisture, wind regimes) · Dynamics of mid-latitude winter storms · Snowpack development, analysis of snow profiles · Deposition patterns and ecology · Avalanches and disturbance ecology.

Readings:

• WEH Chapter 2.
• Scanned Fig 28 (pdf file, 6.5M).  This figure on snow classification did not reproduce well in recent printings of WEH.  This file is scanned from an earlier printing.
• Interested in more? LC Chapter 2 -- a different presentation, w/ overlap

• Handouts:
• Climate and snow lecture handout (pdf, 700k)
• jpg version of the figure Air mass sources and flow patterns influencing the climate of the US Rocky Mtns - from "The Southern Rockies" by A. Benedict and B. Bash (1991, Sierra Club Books, SF)
• Daily Weather Discussion handouts: Archive

 

Current Conditions & Forecasts - Current MRS weather: Niwot wx stations, Saddle stn TundraCam NWS Forecasts: MRS, Niwot treeline (11,000') Nederland, Northern Mountains NWS Graphical Forecast: Cenral Rockies Regional snow forecast: Colorado & SW U.S.  National context - ~North American Snow Cover: & Snow Depth [Northern Hemisphere Snow Depth] US current conditions: 4 panel [components: sfc T, moisture: dew point T, sfc pressure/wind, sfc pressure trend]  Unisys National Forecast (including current Satellite and Radar) General atmospheric circulation -  Unisys Mid-Tropospheric (500mb) wind and heights, showing position and strength of the mid-latitude jet: current and forecast Jet Stream simple graphic Colorado Avalanche Forecast -  High elevation 24-hr weather record: Loveland Pass (table, graph), Berthoud Pass (table, graph), other stns.  Note: data are in US units (°F, mph) Regional Wx & Avi forecasts: Front Range, Steamboat.  Link to other regions from these pages. Windchill Chart:  up to 60 mph - pdf (200k), up to 150 - Mt Washington link CDOTRoad Conditions: Traffic Cameras (SH72: Ward), Front Range Hwys Archive of Daily 500mb, Surface (sea level pressure, surface temperataure, precipitation), and Avi forecasts: Week I: 8 Feb 09: 500mb, Sfc, CAIC Week II: 14 Feb 09: 500mb, Sfc, CAIC Week III: 21 Feb 09: 500mb, Sfc, CAIC Week IV: 28 Feb 09: 500mb, Sfc, CAIC

• Other Resources: 
• Progression of Snowcover over North American, Winter 2001-2002:  movie clip (mpg, 4M)
• Mountain Weather & Climate, by Roger G. Barry (2nd ed., 1992.  Routledge, NY)   [QC993.6 .B37 1992]
• Mountain Meteorology, by C.David Whiteman (2000.  Oxford University Press, NY)  [QC993.6 W48 2000]
• "Snow and ice crystals." by Y Furukawa & JS Wettlaufer.  Physics Today, December 2007, page 70 (pdf) or <http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_60/iss_12/70_1.shtml>
• more on the physics of snowflakes by Y Furukawa:  link
• drawning of snow crystals by René Descartes in 1637 (jpg): Physics Today story

 

Bring:	Field Journal compass topo map pack lunch If you have:  Hand lens snow shovel
Handouts:	Snowpit protocol & snow crystal ID handout (pdf, 3.3M) Snowpack Profile datasheet (pdf, 60k)  Niwot Ridge Sites (doc, 130k) - edit to add field collection sites as needed
Related links:	Niwot Ridge LTER Climate page  see also other version MRS Mountain Climate Program Glossary of Snow & Avalanche Science Terms Depth Hoar - http://www.avalanche.org/%7Euac/encyclopedia/depth_hoar.htm Example snowpack analysis related to an avalanche accident report: Berthoud Pass - 6 Jan 2007 (CAIC)
More:	Climate station locations: Map, Elevation profile showing most stns Snowpack history = Stn C1 Monthly Snowpack Reports - Kurt Chowanski, MRS for 2008/09 - 31 Dec 08, 31 Jan 09, 28 Feb 09 Previous Years-  2007/08 - 31 Dec 07, 31 Jan 08, 29 Feb 08 2006/07- 29 Dec 06, 31 Jan 07, 28 Feb 07 Regional snowfall maps of the two Dec 06 major storms: http://www.crh.noaa.gov/bou/?n=winter2_storms 2005/06: 16 Dec 05, 30 Dec 05, 31 Jan 06, 28 Feb 06

• Results

 

2009	This year's results -  2/08/09 Snowpack profile datasheets (pdf, 700k), blackboard  graphs (Forest, OpenShallow, OpenDeep sites: jpg's, 800k - c/o Sara Fairchild) 2008-09 Winter weather record up through Snowpit day - C1 new snow and temperature record (charts: pdf, 40k - data: xls, 70k) - from Kurt Chowanski
2008	2/10/08 Snowpack profile datasheets (pdf, 720k), blackboard  graphs (jpg, 3M - c/o Kurt Chowanski) Pit 1 T profile plots (pdf, 200k) & data (xls, 40k)
2006	2/19/06 Snowpack profile datasheets (pdf, 900k), blackboard  graphs (jpg, 1.3M - c/o Jyh) Red dust layer Photos of the red dust layer, 15-16 Feb 06 event:  CAIC site, MRS & Niwot Ridge photos effects of dust layer continue through season: 30 April 06 snowpack report Retrospective article: Intermountain West Climate Summary
2005	Spring '05 snowpack profile datasheets (pdf, 380k)