Another player is land-surface feedbackswetter soils provide more moisture to the air through evaporation. Cambrian trilobites from the Bright Angel Shale (Tonto Group), Grand Canyon National Park, Arizona. Columbian mammoth (Mammuthus columbi) tracks, Pleistocene, White Sands National Park, New Mexico. The oceans between Gondwana and North America began to close. During much of the year, the prevailing wind over northwestern Mexico, Arizona, and New Mexico is westerly (blowing from the west) and dry. Because warm air can hold more moisture than cool air can, convective mixing with cool air forces moisture to condense out of warm air as vapor (clouds) and precipitation. These changes to rain and snow-pack are already stressing water sources and affecting agriculture. NOAA (National Oceanic and Atmospheric Administration). The North American Monsoon is a seasonal change in the atmospheric circulation that occurs as the summer sun heats the continental land mass. While the state is generally arid, its high western mountains experience more precipitation each year than the desert southwest and the high northeastern plateau do. Regional overview Southwest. Despite the areas arid climate, the dunes were surprisingly full of life, particularly in southeastern Utah. :https://earthathome.org/de/what-is-climate/, Digital Encyclopedia of Earth Science: Evidence for and causes of recent climate change:https://earthathome.org/de/recent-climate-change/, Digital Encyclopedia of Earth Science: Climate change mitigation: https://earthathome.org/de/climate-change-mitigation/, Digital Encyclopedia of Earth Science: Climate change adaptation: https://earthathome.org/de/climate-change-adaptation/, [emailprotected]: Quick guides & FAQ: Climate and Energy:https://earthathome.org/quick-faqs/#climate, [emailprotected]: Here on Earth: Introduction to Climate: https://earthathome.org/hoe/climate/. Deer mice are the most important rodent carriers of hantavirus in the Southwest. For example, parts of the Colorado Rockies experience cool annual temperatures and over 8 meters (25 feet) of snowfall every year, while the dry deserts in southwestern Arizona receive only about 8 centimeters (3 inches) of precipitation a year and can experience as much as a 15C (60F) degree temperature difference between night and day. The Sonoran Desert is located in southwestern Arizona and adjacent regions of California and Mexico. For example, the difference in annual mean temperature between Pikes Peak (4302 meters or 14,114 feet) and Las Animas (1188 meters or 3898 feet), only 145 kilometers (90 miles) to the southeast, is equivalent to that between Iceland and southern Florida! This feature provides a closer look at trends in temperature and drought in the southwestern United States. Other elements involved in the ignition and growth of fires and the risks they pose to people living in the Southwest include (but are not limited to) forest management practices, development patterns, and human behavior (intentionally or unintentionally starting fires). The warmest temperatures in the Southwest are found in Arizona and New Mexico, while the coolest are found in Utah and Colorado. Nighttime winter temperatures in the desert can drop slightly below freezing. The state's mountainous areas, however, have climate characteristics that more closely follow those found in the Colorado Rockies. The map in Figure 1 shows how average annual temperatures in the Southwest from 2000 to 2020differed from the average over the entire period since widespread temperature records became available (18952020). Because high mountains to the west and north act as a barrier to cold Arctic air masses, most areas of Utah rarely experience temperatures below freezing or prolonged periods of extreme cold. Fossil mammals adapted to colder temperatures are found in the Pleistocene of Colorado. During the winter, moisture travels from the west, as storms from the Pacific Ocean move east. Left:Trilobites identified asDolichometoppus productusandAlokistocare althea. After the end-Cretaceous bolide impact, the climate may have cooled briefly, but it soon rebounded to a warmer state. Photograph by Bill Morrow (Flickr;Creative Commons Attribution 2.0 Generic license). This chapter builds on assessments of climate change in the Southwest region from the three previous U.S. National Climate Assessments. Cities like Phoenix, Las Vegas, Yuma, and Palm Springs have average highs over 100 F (38 C) during the summer months and lows in the 70s or even 80s. NWS Climate Prediction Center College Park MD. Data for Figures 1 and 3 were obtained from the National Oceanic and Atmospheric Administrations National Centers for Environmental Information, which maintains a large collection of climate data online at: www.ncdc.noaa.gov/cag. USA 107(50):2125621262. A large, low-latitude desert formed along Pangaea's western margin, generating extensive dune deposits. The better known of these wet seasons is the summer monsoon, which lasts from about mid-June to early September. Las Cruces is located in the Basin and Range region of New Mexico. Regarding changes that have already occurred, the report finds modest evidence that the monsoon rainfall has intensified since the 1970s, and this has been partly attributed to greenhouse gas emissions. Another factor besides latitude and elevation that influences temperature in the Southwest is its arid climate. Flows in late summer are correspondingly reduced, leading to extra pressure on the states water supplies. The daily range between maximum and minimum temperatures sometimes runs as much as 50 to 60 degrees F during the drier periods of the year. For example, high winter temperatures between 2000 and 2003 correlated to bark beetle outbreaks that devastated pinyon pine throughout the Southwest, leading to nearly 90% mortality at some sites in Colorado and Arizona. (2015) . Submitted by rebecca.lindsey on Thu, 09/30/2021 - 10:15, Science & information for a climate-smart nation. In the Southwest, average precipitation ranges from only 34 centimeters (13.4 inches) in Utah to 39.9 centimeters (15.7 inches) in Colorado, which reflects the area's general aridity. Alaska weather and daylight varies wildly by region and season, from short-sleeves in summer to down jackets in winter; from 7 rainy days in May in Southcentral to 17 rainy days in the Inside Passage. Bear Lake and Glacier Gorge, Rocky Mountain National Park, Colorado, 2011. Unless otherwise indicated, text and images on this website have Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licenses. MacDonald, G.M. There is a rich marine fossil record from the areas between these islands. Light precipitation travels eastward over the Sierra Nevada and Cascade mountains after dropping heavy snowfall in areas of high elevation. Drier days and higher temperatures will amplify evaporation, increasing the desertification of already arid areas and affecting natural ecosystems as well as increasing pressure on the water supply for agriculture and cities. During this time, the only exposed areas were islands in western Colorado and parts of New Mexico. Precipitation also varies widely. By the start of the Late Cretaceous, this inland sea, called the Western Interior Seaway, divided North America in two; the water was rich with mosasaurs, giant clams, and other marine life. Shiprock, a volcanic monadnock in San Juan County, New Mexico, rises roughly 483 meters (1583 feet) above the desert plain. What happened that make TS Nora so underwhelming? Since the early 1900s, the Southwest has experienced wetter conditions during three main periods: the 1900s, 1940s, and 1980s. Skeleton of a juvenileCamarosaurs lentus, a type of sauropod, from the Carnegie Quarry, Jurassic Morrison Formation, Dinosaur National Monument, Utah and Colorado. So is climate change increasing monsoon variability? While two indicators in this report present information about unusually high or low temperatures and drought on a national scale (see the High and Low Temperatures indicator and the Drought indicator), this feature highlights the Southwest because of its particular sensitivity to temperature and drought. July 1August 22, 2021 precipitation shown as a percent of the average July 1August 22, based on 19792020. In 2000-2003, the combination of severe drought and unusually high temperatures led to a significant die-off of pion pines in the Four Corners region of the Southwest. Title: Arizona Monsoon Thunderstorm. The supercontinent was split by spreading along the mid-Atlantic ridge, initiating the formation of the Atlantic Ocean. This mortality is attributed to higher temperatures, drought, and the eruption of bark beetles that are able to survive through warmer winter weather. Photo by Kenneth Carpenter (Wikimedia Commons,Creative Commons Attribution-ShareAlike 4.0 International license, image cropped and resized). Large lakes formed in low areas, and the Southwests most striking ice age feature was Lake Bonneville, a massive pluvial lake that covered much of Utah. Since then carbon dioxide emissions have been on a downward trend. Smog (haze caused by air pollution) over Salt Lake City, Utah, 2016. Images by Lauren Dauphin, NASA Earth Observatory (used following NASA's image use policy). Natural variability, changes in irrigation practices, and other diversions of water for human use can influence certain drought-related measurements. The Southwest's overall average high temperature of 19.2C (66.6F) and average low of 2.8C (37.0F) are indicative of a varied climate, one much less uniform than that found in many other parts of the United States. Extensive Permian deposits throughout the Southwest are home to a host of fossils, including terrestrial amphibians, reptiles, and synapsids. Summer heat waves will become hotter and longer, while winter cold snaps will occur less often. Extreme high temperatures. Is the tropical storm season done for this part of the country? Where the land was exposed, deposits of dust (loess) accumulated and were blown across much of the Southwest. Photo by Gregory Smith (flickr, Creative Commons Attribution-ShareAlike 2.0 Generic license, image cropped and resized). Ill be back on my regular beat in a couple of weeks with the September ENSO update. Image adapted from an image by Scenarios for Climate Assessment and Adaptation, first published in The Teacher-Friendly Guide to the Earth Science of the Southwestern US. Since 800,000 years ago, an equilibrium has been reached between warming and cooling, with the ice caps growing and retreating primarily due to the influence of astronomical forces (i.e., the combined gravitational effects of the Earth, Sun, moon, and planets). The thunderstorm begins. Go to the full list of resources about the climate of the southwestern U.S. Go to the full list of general resources about climate. An ancient horse (Mesohippus),Eocene Florissant Fossil Beds, Teller County, Colorado. North America's position near the equator kept its climate relatively warm. Left:A petrified stump. In the Southwest, climate change may impact a variety of resources, including water availability in the form of snowpack and spring streamflow, the distribution and composition of plant communities, and fire regimes. Submitted by rebecca.lindsey on Thu, 09/30/2021 - 10:14. That timeworn classic is only partially true--May and September can also be great summer months. By the late Carboniferous, North America had collided with Gondwana, leading to the formation of Pangaeaa supercontinent composed of nearly all the landmass on Earth. Changes in atmospheric pressure during the late fall and winter can lead to an accumulation of haze. For many of us, the word monsoon conjures images of heavy rain lasting for months. All rights reserved. Average yearly tornado watches in each county of the United States between 1993 and 2012. Accessed March 2021. www.ncdc.noaa.gov/cag. Calf Canyon-Hermit Creek Fire near Holman, New Mexico, on May 8, 2022. Taken on August 15, 2016. Glaciers in the Colorado Rockies are sustained largely by avalanches and wind-blown snow. Photo by Santa Fe National Forest (National Interagency Fire Center on flickr, public domain). At this time, the Southwest was still submerged. The formation of precipitation also causes electrical charging of particles in the atmosphere, which in turn produces lightning. The Southwest is typically dry, hot, and humid. Sprawling development of Phoenix, Arizona, a city in the Sonoran Desert, 2009. Well those extra storms probably just go somewhere else because of the change in wind pattern that the El Nino brings, eh? Some areas were more than 2F warmer than average (see Figure 1). Trees killed by bark beetles at Cameron Pass, Colorado, 2011. Summer temperatures on the South Rim, at 7000 feet (2134 meters), are especially pleasant from 50 to about 85 F (10s to 20s C). Bark beetles, which normally die in cold weather, have been able to survive through the winter and reproduce, increasing tree mortality.