[pct-l] Rains washout PCT bridges in Washington State

[rogers at isi.edu (Craig Milo Rogers)]

On 03.10.29, AsABat wrote:
> Could you please send whatever rain you don't want to San Diego? The trail
> sure needs it before it gets burned up.

	Not so quickly, please!  Have you seen how much excess rain
they get?  More in a week than Los Angeles' annual rainfall, maybe?
Do you know what that'd do to our hillsides?

	I was saving this for later, but you've given me a perfect
opening, so here goes.

	Some people say that Los Angeles has no seasons.  Not true!
In fact, here's a rhyme to help you remember our seasons (at least, the
seasons near the beach, it's different in the mountains):

    Fire and flood
    Are followed by mud,
    A season of fog,
    And a season of smog.

	Right now we're at the end of October in the season of Fire.
If we get too much rain, we'll enter a season of Flood (initial excess
rain causes the riverbeds to overflow, even the ones with clean
concrete linings).  We want a nice, gentle rain to start with, none of
this harsh Pacific Northwest deluge stuff.  Let's skip Flood this year,
please!

	As the rain continues, the soil saturates, and we enter the
season of Mud.  Hillsides give way.  Houses slide into the ocean.
Engineering geologists get lots of business.  We don't want too little
rain, 'cause that's make a drought and we'll get a nastier-than-usual
season of Fire later in the cycle.  But if we get too much rain, well,
that's bad, too.

	Next, here at the coast, we get the June Gloom: an endless
period overcast or foggy days, that often starts in May and lasts
maybe through August.  When that clears, along comes the inversion
layer (actually, I'm not absolutely certain about the timing here, so
just go along with the story) and we get really polluted air, even at
the coast.  Inland, it just bakes through both Fog and Smog; none of
this coastal moisture nonsense.

	Finally, September and October return, bringing with them the
downslope compressional heating of the Santa Ana winds.  The hot, dry
winds strip the last vestiges of moisture from the chaparral, and we
return again to the furious season of Fire.

	Seriously, although we don't typically get quite the same
level of storm damage to our trails as Washington just experienced,
recently burned areas are prone to all sorts of nasty erosional
difficulties in Southern California.  The trail may wash away, or the
hillside above the trail may wash down on top of it (they're different
cases when you rebuild the trail afterwards).  A governing agency
(BLM, FS, NPS, State Park, etc.) may close a trail for while, perhaps
a year, to allow new growth to stabilize the hillsides, before the
trail is repaired and reopened.

	A trailhead access road may wash away, or have lots of rocks
fall on top of it, or both!, and it might be years, even decades (I
kid you not), before it's reopened, if at all.  Why bother?  The
hikers can simply walk a little farther, after all.  ;-) Or, if
there's enough rain, the frogs will come out, then the next year
it'll be drier, and the frogs will decline, and pretty soon people
will yell and scream about endangered frogs!  When I was a kid, we
used to drive to Hardluck Campground (and beyond, I think) whenever
we wanted.  Not now! Frogs rule! :-)

http://www.fs.fed.us/r5/scfpr/documents/riparian-bo.pdf

	So, please don't send us too much rain, especially all at once.

					Craig "Computer" Rogers