In a lab experiment during eighth grade science class, we tracked the temperature of a flask of water over time as we heated the water over a Bunsen burner at a constant rate. The slope of the graph was steady until the temperature reached the boiling point of water, after which the water temperature leveled off at 212 degrees. Where was the heat going as the water boiled away? It was changing the phase of the water from liquid to gas, where it was stored as latent heat.
When water vapor condenses, that latent heat is released into the surroundings. This is why snow melts much faster when the air is humid; lots of latent heat is released when all that humidity in the air condenses as it comes into contact with snow. The air has been quite dry the past couple of weeks, resulting in a slow melt of the snowpack so far.