page_title: Colorado Springs, Colorado
section_title: Climate
hierarchical_section_title: Colorado Springs, Colorado / Geography / Climate
caption_attribution_description: English: Famous photograph of Serbian-American inventor Nikola Tesla in his laboratory in Colorado Springs around 1899, supposedly sitting reading next to his giant "magnifying transmitter" high voltage generator while the machine produced huge bolts of electricity. The photo was a promotional stunt by photographer Dickenson V. Alley; a double exposure. First the machine's huge sparks were photographed in the darkened room, then the photographic plate was exposed again with the machine off and Tesla sitting in the chair. In his Colorado Springs Notes Tesla admitted that the photo is false: "Of course, the discharge was not playing when the experimenter was photographed, as might be imagined!" Tesla's biographers Carl Willis and Mark Seifer confirm this. During 1899-1900 Tesla built this laboratory and researched wireless transmission of electric power there. The Magnifying Transmitter, one of the largest Tesla coils ever built, with input power of 300 kW could produce potentials of around 12 million volts at a frequency of about 150 kHz, creating 130 ft. (41 m) "lightning bolts". The arcs in the image are 22 feet long. When he first turned it on, the machine blew out the Colorado Springs power company's generator. These long arcs were not a feature of the normal operation of the coil because they wasted energy; for these photos Tesla forced the machine to produce arcs by switching the power rapidly on and off. The photo was part of a publicity spread taken by photographer Dickinson Alley in December 1899 to accompany his magazine article Nikola Tesla, "The Problem of Increasing Human Energy", Century Magazine, The Century Co., New York, June 1900, fig. 8; a version without Tesla appears in the article. The note accompanying the image: "Fig. 8 - The coil, partly shown in the photograph, creates an alternative movement of electricity from the earth into a large reservoir and back at a rate of one hundred thousand alternations per second. The adjustments are such that the reservoir is filled full and bursts at each alternation just at the moment when the electrical pressure is maximum. The discharge escapes with a deafening noise striking at an unconnected coil twenty two feet away, and creating such a commotion of electricity in the earth that sparks an inch long can be drawn from a water main at a distance of three hundred feet from the laboratory. This copy was sent to British physicist William Crookes, and is inscribed: 'To my illustrious friend Sir William Crookes of whom I always think and whose kind letters I never answer! Nikola Tesla June 17, 1901' Wellcome Images Keywords: Electrical energy; Electric; Power; Electricity; Energy; Volt; Power (Psychology); Static; Voltage; Laboratories; Nikola Tesla
context_page_description: Colorado Springs is a home rule municipality that is the largest city by area in Colorado as well as the county seat and the most populous municipality of El Paso County, Colorado, United States. It is in east central Colorado, on Fountain Creek, 60 miles south of Denver.
  At 6,035 feet the city stands over 1 mile above sea level, though some areas are significantly higher and lower. Colorado Springs is near the base of Pikes Peak, which rises 14,115 feet above sea level on the eastern edge of the Southern Rocky Mountains.
  The United States Air Force Academy opened just north of Colorado Springs in 1958. The city is home to 24 national sports governing bodies, including the United States Olympic Committee, the United States Olympic Training Center, and USA Hockey.
  The city had an estimated population of 478,221 in 2019, and a metro population of approximately 738,939, making it Colorado's second most populous city, behind Denver, and the 39th most populous city in the United States. The Colorado Springs, CO Metropolitan Statistical Area had an estimated population of 712,327 in 2016.
context_section_description: Colorado Springs has a cooler, dry-winter semi-arid climate (Köppen BSkw), and its location just east of the Rocky Mountains affords it the rapid warming influence from chinook winds during winter but also subjects it to drastic day-to-day variability in weather conditions. The city has abundant sunshine year-round, averaging 243 sunny days per year, and receives approximately 16.5 inches (419 mm) of annual precipitation. Due to unusually low precipitation for several years after flooding in 1999, Colorado Springs enacted lawn water restrictions in 2002. These were lifted in 2005.
  Colorado Springs is one of the most active lightning strike areas in the United States. This natural phenomenon led Nikola Tesla to select Colorado Springs as the preferred location to build his lab and study electricity.
caption: Nikola Tesla sitting in the Colorado Springs Experimental Station with his "magnifying transmitter" generating millions of volts
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