GC 170 1st Edition Lecture 18 Outline of Last Lecture I Climate Change Impacts a Arctic Sea Ice i Changes over the past years b Ice Sheets i Consequences ii Dynamics c Glaciers i Photography II Sustainable City Assignment Outline of Current Lecture I Weather vs Climate II Drought a Definition b California c 1930 s Dustbowl d 1950 s Drought e Consequences f Wildfires i 2002 ii 2011 Current Lecture I II III Weather The state of the atmosphere at any given place or time a Rainstorms b Tornadoes c Blizzards d Hurricanes e Heat wave Climate The long term average of weather in a given place a Refer to typical weather patterns i Monsoon rains in Tucson Drought prolonged period of dry weather lack of rainfall that results in a serious water shortage These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute a Defined by i Severity how dry ii Length of years iii Special extent b California currently in severe 3 4 year drought i Jet Stream 1 The jet stream ridge prevents storms from reaching California for several months and decreases rainfall for multiple years ii Global Change type drought 1 A drought episode with warmer temperatures 2 Leads to more evaporation and drier soils 3 Regional droughts iii Why 1 Natural Variability a La Nina Events b Sea surface temp in northern Pacific 2 Global Warming a Expansion of Hadley Cell Circulation b Jet Stream Patterns c 1930 s Dustbowl i Widespread for several years ii Covered big portion of US iii Mass migration of people d 1950 s Drought i Severe drought in SW and Central US ii Not as long or as extensive as 1930 s iii Led to tree mortality crop failure e Medieval Warm Period i Periods of extended drought and low stream flow f Consequences of prolonged and severe drought i Loss of crops ii Less water available iii Forest Mortality iv Wildfires g Global warming and extreme weather i Potential for increases in heat waves 1 A period of very warm temperatures for a few days to weeks 2 Can lead to death in elderly or vulnerable populations 3 Damage to crops and livestock ii Increasing likelihood of record temperatures h Wildfires i 2002 severe drought across the intermountain west 1 Fire activity increased sharply in early 2002 s 2 Colorado Arizona ii 2011 severe drought in Texas 1 Wallow Fire Arizona a 841 square miles b Biggest wildfire in Arizona c 6 000 people evacuated d 32 homes destroyed e 109 million in fire fighting and damage costs 2 Texas Wildfire a Beginning of fire season West Texas i 200 homes destroyed b End of fire season East Texas i 2000 homes destroyed 3 Bastrop County Complex Fire a Exceptional drought that had been ongoing for months b Sparks from a powerline started the fire c Huge winds because of a nearby tropical storm d Consequences i 2 000 homes in one weekend ii 2 firefighters were killed iii 3 4 billion in fire fighting costs economic losses timber homes infrastructure iii Relation between increasing temperatures and wildfires 1 Increase in the number of fires and warmer temperatures across the western US for the past 40 years 2 Warmer temperatures create a longer summer season iv Preparations 1 Fire adapted communities 2 Wildland Urban Interface WUI
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