Truck in my lane! Full brake application. (Canada)

I was descending American Mountain, travelling East on Highway 1 near Hope, B.C., when I came around a corner and another semi-truck was climbing the hill in my lane. A massive rock slide was blocking both westbound lanes, and a highway maintenance crew member was directing traffic. Both the other truck and the maintenance worker failed to alert me on their radios, so I had to apply a full break application to be able to stop in time and avoid a collision. I don’t hold the other truck at fault, because he was waved through, but in my opinion, the highway worker needed to close the highway or radio oncoming traffic, as this occurred in a blind corner and on a hill.

It looks like the rock fall just happened, the poor guy had just come across the situation, what could he possibly do other than call for help ? It was nobody’s fault.