Strong Thermal in North Dakota

From the AP:

POSTED: 10:21 am EDT May 9, 2006

TRENTON, N.D. -- Swirling wind swept a trampoline into
the air and over a fence as a 4-year-old girl was jumping
on it, knocking her unconscious and breaking her arm
and pelvis, witnesses told police.

Grace Hove was hospitalized after Sunday's freak accident
with the broken bones as well as a dislocated jaw and
bruises to a lung and kidney, her mother said.

'She's expected to make a full recovery,' Rae Hove
said Monday. 'Thank God. It could have been worse.'

Witnesses, including two adults, reported the trampoline
was lifted as high as 25 feet, Sheriff's Capt. Bob
Stancel said.

'One man saw the whirlwind, then he saw the trampoline
fly up into his view,' Stancel said. 'He said it was
as high as the trees.'

The trampoline landed partly on a highway with the
girl pinned underneath, he said.

The swirling wind might have been a 'dust devil,' a
localized, spinning pocket of air, said Jim Assid,
a National Weather Service technician.

Such meteorological oddities can occur when air heated
by the ground rises rapidly through the cool air above
it, Assid said.

Dust devils as large as 10 feet wide and 13 miles tall
have been documented, he said.