I live about 7 minutes from an off leash dog park that has dozens of miles of trails on about 220 acres. It's also a big bicyclist destination, and on spring and fall weekends, there will be hundreds of people all over the trails. I've been going here 3-4 times/week for about 4 years.
Every time I walk along the creek at Walnut Creek dog park, I walk (or sometimes sit) under the big limestone overhang and think; "someday, this will all fall to the ground I'm standing on"
See, I knew it!! I... predicted it Notice the sheer dirt wall it left along the top of the ridge, almost as if it was cut with a knife! It's about 10 feet deep/thick, then about 20 feet of limestone below that, give or take. Guess how tall this pile of giant rocks is... Yes, you can see below that Jackson and Alfie climbed it
It blocked off the entire creek, which is about 15 feet wide normally. Below you can see how little water is left on the other side. The trees you see on the left, piled several feet high in dirt, are actually many of the trees from the top of the ridge, before it fell, they just haven't started to turn brown yet. These photos were taken about 6 hours or so after this happened.
In the photo below, in the center, you can see some black spots, almost in vertical lines. If you zoom in slowly, you'll see the marks better and realize they are on the sheer face of the wall where the rock sitting at the 45 degree angle to the left just 'broke off' from the rest of the wall. The section of wall that you can see the marks on is about 10-12 feet deep/thick. This is basically where I was sitting in the first photo. Can you imagine how loud that was!?
The dogs below help show the scale.
I figure it's about 80-100 linear feet of cliff that all dropped at once today.
If this had happened 48 hours earlier, there would have been from 4 to 40 people where this came down, some with a long way to run in any direction if they acted immediately. As far as I know, no one was hurt, but how would you know this soon?