If you have the chance to go on a bonfire during winter, cast a snow chunk on to the fire. You will observe that the chunk will slowly melt given the size and heat of the fire. On a layman’s point of view, water actually can take a great quantity of heat in raising its temperature.
The snow melted probably because it gave some cooling power to the fire surrounding the snow. The question is, the fire could be very hot and there is a belief that any object has only certain capacity to absorb extreme heat at a given time and any heat added in this case is wasted. This explains the process of melting in a layman’s point of view.
On the scientific side, there are 2 ways to transfer heat into the snow block. The heat that comes from something like sunlight known as radiant heat will not have the capacity to force its strength against a snow block because it can discard much of that heat away.
The size of the snow block could have been much cooler than the heat of fire and has the potential to impede the rise of hot air with its own coolness thus somehow protecting itself as it melts.
Considering the amount of heat involved, the fire heated the block snow reaching its melting temperature subsequently followed by heating the melted snow to its boiling point and the process of transforming it finally from liquid to vapor.
As the fire was attempting to reach the boiling point of the snow, the water beneath was also trying to drip into the fire below, not to cool it but slow it down to the extent of trying to extinguish the fire on the surface below.
From this point of situation, there are 3 theories involved in the process of slowing down the melting process. The first theory concerns the cooling power of the ice to cool down the fire in such a way that it hindered its full strength to melt the snow immediately.
The 2nd is that the snow was not strong enough to absorb the heat and be melted right away considering that it is not a combustible object. This is the reason why it melted slowly. The 3rd is that it needs a strong amount of energy to turn the ice crystals to vapor.
The air surrounding the ice is not an effective heat conductor and has a very low heating capacity. This can be further explained in the scientific process of heating capacity and conductivity. Water has a high heating capacity and it absorbs too much energy transforming from solid to liquid, and liquid to gas.
You can test this when you finish your shower, you feel so cold. This is because water consumes a lot of heat in vaporizing off your body temperature. In case of ice, it can help to keep the ice colder for a little longer if put into fire. The driving force that induces heat transfer is temperature.