Breaking News
NASA Satellite Reveals Heavy Rainfall Patterns
01.11.05
Above: Rainfall accumulation in San Diego over five days. Colors range from a low amount of rain shown in green, to amounts of over 200 mm (nearly eight inches), shown in red. As the "Pineapple Express" moves in from Hawaii, it brings these increasingly heavy waves of rain. Click on image for movie or download high resolution still. Credit: NASA/NASDA.
The flow of moisture originating from near Hawaii known as a "Pineapple Express" along with a persistent low pressure system over the region are to blame for California's recent spate of mudslides and extreme rains. The Pineapple Express originates in the subtropics near Hawaii and acts as a conveyor belt of moisture. This moisture can interact with storm systems rotating around an area of low pressure off the coast of California as in the current situation. While the string of five days with continuous rain is unusual in California, it does occur once every 10 to 12 years according to the National Weather Service.
This image shows rain accumulation in San Diego from Jan. 6 through Jan. 11 based on data from the Tropical Rainfall Measuring Mission (TRMM)-based Multisatellite Precipitation Analysis. The accumulation is shown in colors ranging from green (less than 50 mm of rain) through red (200 mm or more).
The TRMM satellite, using the world's only spaceborne rain radar and other microwave instruments, measures rainfall over the ocean. In this case instruments were able to reveal rainfall structure resulting from storms "riding" the actual Pineapple Express extending toward Hawaii, which is beyond the range of conventional land-based National Weather Service radars.
In early 1995, a Pineapple Express hit California, contributing to a season of winter storms that killed 27 people and did $3 billion in damages and costs. A Pineapple Express in mid-October 2003 wreaked havoc from south of Seattle to north of Vancouver Island. Flooding forced more than 3,000 people from their homes.