They counted the western wintering population of Monarchs and their numbers have plummeted by 86 percent. I believe this is due to the western milkweeds that grow all year round. Because they don't die back to the ground they build up huge ammounts of the OE pathogen. You western milkweed growers need to wake up and start cutting back your plants and sanitizing them to stop the spread of this disease. There might not be any wintering western Monarchs at all next year!
http://blogs.edf.org/growingreturns/2018/12/04/western-monarch-butterfly-population-decline/