On 10/20/2011 10:53 AM, Rich Grise wrote:
....

Have any of those grass fires been started by dry lightning?
....

Yes, that's another moderately common source and was essentially the
only source during the evolution of the high plains prairies. Of
course, back then, when one started it burned until it reached a river
(and it can be a _long_ way between them out west) or there was some
associated rain w/ a storm or the wind shifted and blew it back into itself.

The Indians would do like the ranchers in early spring to get earlier
grazing for the buffalo; it's where they (early ranchers/farmers)
learned the "trick". Of course, the Indians also used it as a weapon on
occasion.

Last year we had at least a half-dozen on our ground that were started
by lightning but all were extinguished shortly by at least enough rain
that none got larger than 30-40 acres or so. This year being in the
extreme drought conditions we're in, we've had almost no thunderstorms
at all the whole year and only one of 10-15 A. It was directly across
the road from a house and within a couple of miles of town so it was
reported immediately and didn't take the county long to get a truck out
and there was just a sprinkle as well so was only a few acres burned.
It greened up nicely early after the shower, but has had so little rain
all summer that it never did get any growth to speak of on the bare spot
and have started to seem some sifting of the ground. Likely will have
to go and spread some manure before winter is over unless we get some
moisture _real_soon_now_ (tm) which isn't likely as we're going into our
typically driest portion of the year.

We're in the D4 Exceptional area in the SW corner of KS that has S KS,
most of OK and TX in it's bullseye...

http://droughtmonitor.unl.edu/monitor.html

With the advent of settlers there became more sources from human
activity but also they worked to put them out so that for large areas
the frequency of fire is far reduced from its historic average. I've
seen estimates that any given area probably burned at least once every
5-7 years. That combination of fire and relatively low precipitation
produced the prairie environment of tall and short grasses depending on
land type and annual precipitation and eliminated virtually all woody
plants other than along the bottoms in the eastern third or so of the state.