Are New Slides Possible

[RGF1]

With the seemingly endless rain and remaining snowpack I am wondering if the ground has or will be come saturated enough for new slides to occur or for old ones to reslide? I can think of a a lot of places where there could be one . Or does the water percoalte and drain or seep to fast for there to be one now ? Early this Am I used my tracked Bobcat to pull a small Jeep out of a area they should have not been stuck in . They guys in the jeep were going on little known 4x4 raod to check on thier land . The ground was soaked I sunk in just walking on it usually no one would sink in at all there. Now if only the rain will go away .

 

[bridgeman]

The situation leading to the 1999 slide on Colden was an extended dry spell, which caused the root structure to loosen from the underlying rock, followed by a large volume of rain (which hurricane remnant?), super saturating the soil, water started running between the rock/soil interface reducing the friction holding the soil in place and the rest is history.

 

[sapblatt]

The situation leading to the 1999 slide on Colden was an extended dry spell, which caused the root structure to loosen from the underlying rock, followed by a large volume of rain (which hurricane remnant?), super saturating the soil, water started running between the rock/soil interface reducing the friction holding the soil in place and the rest is history.

I am quite sure I have read that many of the WMNF forest slides started in the same way. They tend to occur after dry spells when there is a heavy rain. I think for now the mud is holding everything togeter.

 

[RGF1]

Usualy when ther is a dry spell plants send tap roots deeper. contrrary to what one would think . .I could be that a dry spell then heavy rains set of slides. I am not a hydrologist. . In a way I would not mind if say a few 4 ,000 ft peaks slid and opend up some views . Just no dmage to homes and bussinesess .

 

[Rob S]

followed by a large volume of rain (which hurricane remnant?)

That would be Hurricane Floyd. 3 friends and I were at Whispering Pines campground the night when that slide occurred. Didn't know about it until we got to Marcy Dam next morning and saw the helicopter hovering over the area. A ranger gave us the details, and we had to slightly modify the plans for our 3-day backpack.

 

[Rik]

Usualy when ther is a dry spell plants send tap roots deeper.

I think this is sometimes true but in many place there is a shallow layer of soil on top of solid rock. No where for the roots to go.

 

[Dr. Dasypodidae]

"The situation leading to the 1999 slide on Colden was an extended dry spell, which caused the root structure to loosen from the underlying rock, followed by a large volume of rain (which hurricane remnant?), super saturating the soil, water started running between the rock/soil interface reducing the friction holding the soil in place and the rest is history."

The landslide engineers tell us that "reducing the friction" from increased precipitation is largely a myth, but what happens instead is an increase in pore water pressure between particles in the soil and particles and the underlying bedrock. A numerical model that considers pore water pressure, the coefficient of friction (which is based on particle size and shape and slope angle), and gravity then can be used to determine whether a slope should fail. Highway engineers use these models to calculate "factors of safety," on which basis slopes are commonly reduced in grade (hence increase the coefficient of friction) with bulldozers, dynamite, or whatever.