Bluffs are inherently unstable landforms. They're gone in a geologic eyeblink, which means they can be dangerous. No matter how solid and stable that big, beautiful bluff looks, be cautious around it. Bluffs can kill without warning, as Arch Rock at Point Reyes National Seashore recently did.

One hiker was killed and another injured when a seaside cliff collapsed at a park in California and sent giant boulders and earth plunging onto the beach below, officials have said.


The National Park Service said the area had been closed to the public for safety reasons since Thursday when large fissures appeared at the top of Arch Rock, weakening the cliff.

I don't want to lose any of my readers to a geological mishap, so please, when you're exploring the seashore, be extra special aware of your surroundings. And when you see signs like this:

Please pay attention to what they're telling you. They're not kidding when they say they're unstable!