My two cents...
Front range peaked this past weekend. Different basins peak at different times, and looks like the ark and Durango are past peak too. Yesterday was really hot, which got the high elevation snow to bump a bit more, but not enough to offset declines that are already headed down. I don't think we will see a bump up to a higher peak.
I've spent a fair bit of time correlating snowpack to runoff. My observation is that peak flow typically coincides with snotels going to 0 snowpack left. Snotels are in the 10,000-11,000ft range for the most part, and this is where the majority of the water is stored in watersheds (ie there is a reason they put them there, its the best predcitor elevation for runoff). Sure you still have snow in the 12000-14000 ft range right now, but the amount of acreage that has snow is way smaller than the 10000-11000 ft range.
I read a good study from CSU that did a very rigorous model of the cache la poudre basin, and the conclusion was the same... runoff correlates with snowpack in the 10000 ft range. If you are a snowpack data geek, this is good reading
When there is ample snow in the 10000 ft range, each warm day melts more snow and the rivers rise. You might see 1-2" of SWE come off the 10000 ft snotels each day. Once that goes to zero and summer heat sets in you still get the daily diurnal fluctuations from high elevation melt continuing, but the mid level snowpack that drives peak flows is gone, and so is the ability of the river to rise above peak without a rain event.