BDU/BDC Oak Glen Flooding
Large scale debris flows in Oak Glen
Unified command at 551 with incidents in Forest Falls and Oak Glen
Oak Glen and Forest Falls both cut off due to flows
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Highly unusual for this area.
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Forest fall and the oak glen area have a well documented history of significant and very destructive flash floods, I recall back in early 2000 we/Del RosaIHC were assigned to search and rescue/debris clean up. Do a search and you will be surprised.
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The Forest Falls area specifically but the entire area from 330 to 38 is prone to flash floods and debris flows. There is a significant nexus between fire scars and post fire run off issues and that is especially evident in this area.
The terrain and geography when paired with precip regimes have led to some serious incidents in the area including a fatal incident on Christmas.
The geography is not just steep but impossibly steep with all the runoff leading to just a few drainages and outlets onto the valley floor below. The El Dorado and Line fire’s were classic examples for post fire run off issues. High intensity fire behavior, steep head walled canyons and a population base living in the footprint of an alluvial fan.
The fire intensity can be difficult to gauge from a firefighting perspective. We often think of fast moving fire as being the most intense.. when often it is the slower moving fire burning against a wind that can do the most damage to the soil and specifically the micro flora and fauna which reside in the soil and work to keep the soil alive.
In the brush fuel model in SoCal and specifically the BDU/BDF the soils are primarily DG and prone to slides without a fire stripping everything away.
The second hallmark of post fire runoff concerns is rainfall intensity. High intensity short duration rainfall will lead to debris flows where longer duration but lower intensity rainfall will lead to flooding.
One drive into Angelus Oaks and Forest Falls and you can see the scars of previous high water/mud events.
During the Line Fire near the end of the incident there was a small debris flow near Highland from thunderstorms.
The metrics suggest a 50% reduction in debris flow thresholds the second year post fire, but yesterday’s high intensity and relatively long duration precip event would have caused issues without the fire history.
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We where enroute to a fire in Fallbrook from OVY with a ST of crews. Believe the year was either 96 or 97. We were diverted to Forest Falls because of floods that washed timber thru houses. We used our crews to remove timber from roads and houses. It was a pretty wild scene.
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Was on a trails crew briefly in 99 before starting on fire (and borrowed for a month on Del Rosa).
Was up in the San Gorgonio Wilderness and had to hike back and leave early cause the monsoons moved in and started early one day.
Went home early, and got a call several hours later at home from my dad who was LE in Lytle Creek. Apparently my supervisor at the time didn’t go OOS and where our trucks were parked was under 14 feet of mud. Caused a bit of a headache in dispatch trying to find us.
Good times 
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