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  • Irish Chronicles Document Links Between Volcanoes and Weather
    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong corr...Read more

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    Irish Chronicles Document Links Between Volcanoes and Weather

    A study of over 40,000 written entries in Irish Annals and ice core measurements shows a strong correlation between the occurrence of volcanic eruptions and extreme cold weather in Ireland over a 1200 year period. Data analyzed in this study cover the period from 431 to 1649, during which time up to 48 volcanic eruptions are identified in Greenland ice core records through deposition of volcanic sulfate in annual layers of ice. You can find the study (open access), published on 6 June 2013 in IOP Publishing's journal Environmental Research Letters, at http://iopscience.iop.org/1748-9326/8/2/024035/article. Find out more about how volcanoes can influence climate.
  • EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US
    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, acco...Read more

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    EF-5 Tornado in El Reno, Oklahoma Widest Ever Recorded in US

    The EF-5 tornado that hit El Reno, Oklahoma on May 31st was the widest ever recorded in the US, according to the National Weather Service in Norman Oklahoma. The tornado, which remained on the ground for 40 minutes and reached 2.6 miles across (4.2 km), took the lives of 18 people including storm chasers Tim Samaras, Paul Samaras and Carl Young. For more information on the tornado, visit http://ow.ly/i/2hfDG.
  • Atmospheric CO2 Level Tops 400 ppm
    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm rep...Read more

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    Atmospheric CO2 Level Tops 400 ppm

    During the week of May 13th, the CO2 level at the Mauna Loa Observatory in Hawaii topped 400 ppm repeatedly. Daily levels of CO2 can vary due to weather, and there are seasonal trends as well. The level of atmospheric greenhouse gases continues to increase, now over 120 ppm since the Industrial Revolution began. For more on the Keeling Curve, see http://keelingcurve.ucsd.edu/. Find out more about greenhouse gases and warming.
This photo shows a dramatic lightning display over the plains east of Boulder, CO.
Click on image for full size
Image Courtesy of University Corporation for Atmospheric Research/Carlye Calvin

Types of Lightning

Lightning can take place in several different areas of a thunderstorm. Most lightning (about 80%) occurs within a single cloud and is called cloud-to-cloud lightning. Most of the other 20% of lightning involves a stroke from the cloud to the ground. Damage is usually caused where the lightning strikes the ground. And sometimes lightning can jump from one cloud to another or to the surrounding air.

Most of the lightning we see appears as a single line of bright white light, called streak lightning. However, several other types of lightning can occur.

Forked lightning occurs when a second lightning stroke doesn't follow the same path as the first lightning stroke. It usually follows a zigzagging pattern and appears forked with many branches. Forked lightning can go from cloud-to-ground, cloud-to-cloud, or cloud-to-air.

Ribbon lightning occurs in thunderstorms with high cross winds and multiple strokes of lightning. Winds separate the strokes of the lightning bold, making it look like there are parallel streaks of light. This is a form of cloud-to-ground lightning.

Bead lightning is a relatively rare form of lightning. In bead lightning, the stroke appears to break up into a string of short, bright sections, and looks like a string of beads. This is a form of cloud-to-ground lightning.

Sheet lightning occurs when the actual bolt or flash of lightning is hidden behind the clouds. When sheet lightning occurs the entire sky flashes a glowing white color. This is a form of cloud-to-cloud lightning.

Heat lightning occurs within a cloud, but the observer is too far away from the storm for its thunder to be heard. The sound waves dissipate before reaching the observer. Instead of individual strokes, heat lightning often lights up the entire cloud. This is a form of cloud-to-cloud lightning.

Last modified May 27, 2010 by Becca Hatheway.

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