Here is the Opening Day Letter from the Mammoth Lakes Tourism Board...Wow what a day! Fish On Everyone!
.......What an opener! It was a White Fishmas with the 12" of snow we received, but that didn't stop those who were here from casting their lines. Monitor Pass and Sonora Pass had closed due to the weather but reopened yesterday (4/27). The weather now is looking to be in the upper 60's for the rest of the week, which will make it a great weekend to get out and catch some trout.
Fishing conditions in Hot Creek are good but the water levels are low sitting at 18cfs as of yesterday (4/27). If you can find a good spot, then the fishing is quite good. Recommended fly is a Griffith's Gnat #22 or an extended body blue winged olive 20-22.
The water levels in Crowley Lake are on the rise, and the fishing conditions are decent in most areas, but the fish are spread out. They're also in all different depths of water so use your fishfinder to help you locate those guys.
Some fishermen had good luck at Twin Lakes in Bridgeport with some weighing in just under 11 pounds. Although the weather was pretty tough, they stuck it out and did pretty well. Try using various stick baits like Papalas for trolling or inflated crawlers and power bait (always my go-to) for bait fishing.
Mammoth Lakes Tourism