Slab City

We saw numerous avalanches today that were failing on a persistent weak layer of surface hoar between 40-100cm deep. We suspect they were human triggered remotely with many failing sympathetically at the same time. (See photos.) These avalanches were observed on a north slope, between 1550m and 1700m. Over the 2 way radio we also heard reports of sledders triggering slides that buried the road in debris. While we were out riding around 1800m we experienced shooting cracks. We dug a test pit on an east facing slope and found surface hoar down 65cm which failed with moderate taps in our extended column test. We also dug on a south facing slope at the same elevation and found a buried sun crust down 5-10cm which could be a problem later. The forecast storm snow amounts didnt quite happen - we only saw about 5cm fall throughout the day today. We stayed off of any slopes steeper than 30 degrees.