Envirocast® On-Line Feature of the Week -- April 17, 2007

Melting Midwest Spring Snow

The images in this Envirocast® Bulletin were taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard NASA's Aqua satellite on April 10, April 13, and April 16, 2007. 

 

The first image, taken on April 10, was before the April 11 spring snow storm; the second image, taken on April13, shows the snow cover after the snow storm. The high temperatures in the area rose into the 40s and 50s during the following weekend resulting in significantly reduced snow on the ground, as seen in the image taken on April 16.

Snow Cover Changes in Midwest

In visible images (true color), it is sometimes difficult to tell the difference between clouds and snow on the ground (under mostly clear skies). Of course, if you have access to a sequence of visible images, clouds will typically move in time while snow cover won't. On the other hand, while looking at a single visible image, meteorologists can determine whether a blotch of white is snow cover by identifying rivers or lakes, which early in the cold season, are ice- and snow-free and therefore appear as dark fingers amidst white snow cover.

 

We also provide false color imagery.  In these false color images, cumulus clouds are white, water is black, snow cover is in aqua color (cirrus clouds are also in aqua) and vegetation is green.

Environmental Impacts:

  • Several snowfall records were set on April 11, 2007 as some areas of the Midwest got more than 9 inches of snow.

  • In Michigan, the winter storm brought at least 5 to 7 inches of snow, along with unseasonably cold weather, in an area from Kalamazoo to Grand Rapids.

  • A jet trying to land in heavy snow skidded 50 feet off a runway at Cherry Capital Airport in Traverse City, Michigan, early Thursday. According to the National Weather Service, snow was falling heavily and the temperature was about 32 degrees as the plane skidded. No injuries were reported.

  • In Chicago, more than 550 flights were canceled at O'Hare International Airport because of poor visibility.

  • The 3 inches of snowfall recorded at O'Hare on April 11th surpassed its record for the day of 2.3 inches set in 1957.

  • Milwaukee broke a snowfall record for the date with 7 inches; the previous record of 3.2 inches was recorded in 1997. The town of Taylor, in west-central Wisconsin, had 9.5 inches. North Dakota and South Dakota got about 7 inches of snow.

  • In Minnesota, slick roads apparently caused a pileup involving at least 70 vehicles along Highway 169 just southwest of Minneapolis.

  • Six deaths in the Upper Midwest were blamed on the slick conditions.

Supplementary Material:

NASA's AQUA Satellite:

  • Aqua, Latin for water, is a NASA Earth Science satellite mission collecting about the Earth's water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice. The Aqua spacecraft (formally known as EOS-PM) was successfully launched on May 4, 2002 at the Vandenberg Air Force Base (VAFB) in Lompoc, California. t is flying at an altitude of 705 km (438 miles) observing the Earth, and the life expectancy is 6 years. [Aqua's Orbit], [Animation of MODIS Observing the Earth]

  • Aqua passes south to north over the equator in the afternoon, and thus it passes over us at the same local time every day, approximately 1:30 p.m.

Envirocast® Bulletin is a service of StormCenter Communications, Inc. If you are having trouble downloading an image or if you have any questions, please call StormCenter Communications at 410-203-1316.

Envirocast® is a registered trademark of StormCenter Communications, Inc. Envirocast® content is copyright StormCenter Communications, Inc. and is intended to be used solely for those StormCenter customers using the Envirocast software or receiving Envirocast via e-mail delivery directly from StormCenter Communications, Inc. If you are not the intended addressee/recipient, you are hereby notified that any use of, disclosure, copying, distribution, or reliance on the contents of this E-Mail information is strictly prohibited.