For educational purposes

http://www.bergen.com/morris/stormc200008152.htm

Storm was one for the books Tuesday, August 15, 2000

By CHARLES YOO Staff Writer

The question was asked by everyone from Governor Whitman to retirees whose possessions were washed away before their eyes: How could such a deluge happen?

It's actually quite simple, according to meteorologists, who called Saturday's sustained, heavy rainfall a natural reaction to a disastrous mix of warm and chilled air.

Cold air moved in from Canada at the beginning of August and has dominated the upper level of the atmosphere in the Northeast, which usually has sticky, oppressive heat this time of year.

Tropical air from the south then appeared in the lower level of the atmosphere, bringing moisture -- and brewing disaster.

The cold and warm air clashed right above Sparta.

"It's one of the most amazing things I've ever seen," said Bob Ziff of North Jersey Weather Observers. "The thunderstorm just popped out of nowhere and sat over one area for hours and hours."

Why Sparta?

Meteorologists point to its topography. Like most towns in Sussex County, Sparta is wooded and elevated and surrounded by hills and mountains. That, meteorologists say, made it easy for the stormy sky -- rife with warm and cold air -- to dump all its moisture.

Meteorologist Mike Wyllie called the phenomenon the "orographic effect."

"It causes an unstable condition and results in heavy showers and thunderstorms," he said of the heavy rainfall, which sent excess water from Lake Hopatcong spilling into the Musconetcong River.

Still, Wyllie said, a mini-monsoon that soaks only one particular area is rare.

-- K (infosurf@yahoo.com), August 16, 2000