The models say the snowpack should be melting. Natural variabilty is the excuse for why this hasn’t happened.

The money quote: “Although the amount of water contained in the snowpack has declined over the past century, it has been surprisingly stable since the 1980s”

The excuse: “However, here we show that the contribution of global warming to western U.S. snowpack loss has in reality been large and widespread since the 1980s, but mostly offset by natural variability in the climate system.”

Translation: The models are wrong.

The abstract:

Melting snowpack is a vital source of water in the western United States during the summer, when rainfall is usually scarce. Although the amount of water contained in the snowpack has declined over the past century, it has been surprisingly stable since the 1980s, despite 1 °C of warming over the same period. At first glance, this result might appear to indicate that the snowpack is quite resilient to warming. However, here we show that the contribution of global warming to western U.S. snowpack loss has in reality been large and widespread since the 1980s, but mostly offset by natural variability in the climate system. This result points to a faster rate of snowpack loss in coming decades, when the impact of global warming is more likely to be amplified, rather than offset, by natural variability.

And remember, North America Snowpack is above normal (snow water equivalent) in 2018/2019.