I suspect this hill was geologically unstable from the get-go.
I live in Ocean Hills, Oceanside. I go to Vista a lot. There was this beautiful hill on Vista Way and Foothill that has been destroyed by a developer and turned into what has to be the ugliest man-made structure in Vista, in perhaps all of sprawling San Diego County. Thanks goes to Lennar Construction Co.
How the hill looked pre-destruction.
Shame on the city fathers of Vista for allowing this! This hill appears to be unstable, as the builders are shoring its sides up with hundreds of steel fence poles driven into two levels of retaining wall (running east to west the length of the hill and ditto north to south) apparently into the ground underneath these fences every ten feet or so on and tied together with cable.
I suspect this hill was geologically unstable from the get-go, like the one on La Costa near El Camino Real (above the golf course) that came tumbling down (along with the condos built on it) some years ago.
This is totally consistent with San Diego Reader developer atrocities in Ocean Beach (Issue 10/11/18) "Simple Fix Gone Horribly Wrong" and, same issue, developer designs on ancient hills in San Marcos "Growthzilla set to devour San Marcos". I have one friend who lives near this monstrosity who hates it. The citizens of Vista should protest, but I doubt this largely Hispanic low to mid-income area will stand up to Lennar.