The severe drought that threatens water supplies and a potentially devastating wildfire season is deepening and locking into place across much of the far West, Southwest and Southern Plains, according to new climate data released Thursday.

In California’s Sierra Nevada Mountains, where runoff from the spring snowpack provides much-needed water supplies during the dry season, half of the snowpack’s liquid water equivalent melted in just the past week in some areas, due to temperatures that soared as high as 12 degrees Fahrenheit above average of early April, according to the U.S. Drought Monitor.

To make matters worse, the sudden snow melt in California barely boosted reservoir supplies, which remain well below average across the state.

Officials already knew that the snowpack was unusually thin and would provide below average amounts of water when it melted, considering that the state had its third-driest winter on record, following its driest calendar year in 2013. However, they did not anticipate it would melt so quickly.

The California state snow survey on April 1 found that the snowpack contained just 32% of the average water content at that time of year, when snowpack typically reaches its annual peak. This placed 2014 as among the lowest water-content years on […]