streamers of splattered paint, the tracks of nearly 150 years of tropical
cyclones, hurricanes and typhoons weave across the globe in this map.
The map is based on all storm tracks available from the National Hurricane
Center and the Joint Typhoon Warning Center through September 2006.
The accumulation of tracks reveals several details of hurricane climatology,
such as where the most severe storms form and the large-scale atmospheric
patterns that influence the track of hurricanes (and the clear association
with the warm, tropical waters along the equator, which become the western
Over time, the repeated passage of strong
storms through the same regions creates solid swashes of color: bright
red in the Western Pacific near the Philippines, where numerous Category
5 storms have traveled; orange and gold in the Caribbean and the Gulf
of Mexico, where Category 3 and 4 storms often pass. The blues and
light yellows reveal storms in a weaker state: near the equator, in
their first stages of development; over land, as they run out of steam;
in the mid-latitudes, where they encounter cooler waters.
To the west of South America, the Peru Current snakes
northward along the coast of Chile, Peru, and Ecuador, bringing cool
water from southern polar regions. A similar situation happens off western
North America, where the California current brings cold water down from
Alaska and Canada, resulting in few hurricanes. By the time the sea temperature
warms off Mexico, hurricanes can form again. The cool currents keep waters
from reaching hurricane-friendly temperatures. A similar cold current,
the Benguela Current, flows up the western coast of South Africa, past
Namibia and Angola, keeping those waters too cool for hurricanes as well.
--------modified from Historic
Tropical Cyclone Tracks, NASA Earth Observatory