Why don't cracks reach the ground?

Ok, of course plenty of times they do.

But I was just thinking today that it seems like, more often than not (at least here in the northeast), crack climbs require several moves of face or slab to get into them.

Does anyone know why this is?

My guess was that snow cover or the heat of the ground itself keeps ice from forming in cracks at the base of the cliff, and it's mostly ice (isn't it?) that forms cracks.

Cracks form in most types of rock as a way to relieve pressure that built up when the rock was forming. Ice may be a small factor in the formation of the crack but more than likely is not going to add to any geological forces that took place eons ago.

What you described is common in the black hills as well, and can be a total bummer, but I doubt a few more winters of ice or snow is going to make those cracks grow towards the ground.

I think the appropriate question is, "Why doesn't the ground reach those cracks?"

This book is well worth the time:

Erosion of the ground.

erosion of the ground..... plus water runs from the top down so.... the higher the rock the earlier it had water running through weaknesses.... and it probably hadn't eroded the crack down to the ground yet before it found a weak spot to exit.

At smaller crags it could formed by glacial processes as well as freeze thaw.

Your crack doesn't reach the ground because your legs are too long :)
Sorry - couldn't help myself.

Probably varies by rock type and stuff but because rocks form underground with intense pressure they expand once they're exposed at the surface. More exposed means more expansion so where the rock is at ground level it has not had the time or release of pressure to expand.

And weathering.

And other geology nonsense

Although Kim Kardashian's cracked doesn't reach the ground currently just wait 15 or 20 years.

Why do I feel like maybe we haven't quite hit on the definitive answer yet?

Dave Bn wrote:This book is well worth the time:

I don't have this book...is the answer to my question in there?

hmmm.... interesting geological info on here. Thanks y'all!

limpingcrab wrote:Probably varies by rock type and stuff but because rocks form underground with intense pressure they expand once they're exposed at the surface. More exposed means more expansion so where the rock is at ground level it has not had the time or release of pressure to expand. And weathering. And other geology nonsense

Good call... and I think I have an interesting conter thoug. In the West erosion is a major factor and is an active cliff building process. Erosion here back east isn't so much of a significant process comparatively speaking on a macro scale as it is out there. In fact I would say most cliffs are exactly the opposite, they are being filled in by the accumulation of biomass. My thought was most exposed cliff in the NE were covered by glaciers at one point. Many of them were subject to ramp and pluck process where the outcropping is weighted downwards and cracks from the weight of the glacier and blocks are plucked off the backside. Those cracks are then further expanded and grow from freeze thaw.

^^^^^

Cool, didn't know about cracks formed from the weight of glaciers.