I was in that area this weekend. I primarily heard them on VIPER, but I heard a BOLO transmission on the VHF channel at some point. I wasn't paying close attention, but I think they are primarily using VIPER.
Coincidentally, I heard a conversation on their VHF Fire frequency this afternoon about portable radios not able to transmit through the repeater "again" (implying that whatever technical problem they're having has happened in the past).