Dying from the top down

[Mommyk]

So it has been the hottest year in California so I think my problem may be heat but my plant was beautiful one day and I went out two days later and the entire top of the plant where all the big colas are all shriveled and look like they're dying. The entire bottom is fine. I don't know what to do

 

[GreenMtnGuru]

Pictures please - sounds like you may want to give it a thorough look over for caterpillars or hemp borers.