Melted snow at the roof of hive? Good or bad?

25.01.2019. 08:00

Winter can be a tough time for bees and beekeepers. During winter the goal is not honey production but overwintering the queen. Mostly, winter care includes preparations during fall, but that doesn't mean that beekeepers can rest during winter.

Because of harsh conditions beehive needs proper care or else you risk losing the whole colony. Losing a colony is devastating for every beekeeper, so a lot of effort is put into winter care for bees.

Snow puts the beehive at even greater risk. Beehive in snow can have built up snow all around it, which can block the entrances for the bees. Blocked entrances can prevent them from going out to defecate which can be deadly for the bees.

Regular check-ups on the hive are a must, especially for a beehive in snow. During such check-ups you may have noticed that sometimes the snow at the roof of the beehive is melted, which may have left you puzzled. In this article, we will explain why it happens and should you be concerned about it. However, to have a better understanding of why it occurs, you should know what happens in the beehive during winter.

How honey bees survive the winter?

As a part of survival in the winter, bees start preparing during fall. Since bees are cold-blooded, they cannot survive if exposed to cold weather. To combat harsh winter conditions bees naturally have a system that helps them survive winter months.

Contrary to popular belief, honey bees do not hibernate!

Even though beehive in snow might seem calm and as if all bees are sleeping, that is not the case. Unlike some types of bees and wasps, honey bees do not hibernate during winter. Some bees and wasps have to hibernate because their colony doesn’t survive the winter. Only mated reproductive females survive. Honey bees have systems which help the colony overwinter. If everything goes according to plan, most of honey bee colony survives winter and then grows in population in late winter and early spring. The growing of population before spring gives bee colony a large workforce to collect pollen and nectar.

Preparations for winter

For bees, a stable food source is an essential part of surviving winter. Honey bees store food by collecting a lot of nectar and transform it into honey. Raw nectar has a high water content and would spoil quickly if not turned into honey. Honey is long lasting and can be used as a food source for the colony over the next few months or even years.

What you can do to help bees in making honey is planting plants that provide nectar for bees. By having a diverse collection of nectar sources, bees have a better chance of having plenty of food for the winter. Bees look for the food sources together and alarm each other when they find plants with nectar.

When collecting honey a beekeeper has to be careful to leave enough honey for bees to use in winter. The amount of honey needed by the colony depends on the climate. Honey bees in regions with longer winters need more honey than bees in areas with shorter and milder winters.

Bees are still active in the beehive

Even though the hive might seem inactive from the outside, bees are still active inside the beehive and work to keep the colony alive. However, during warmer days bees might still fly outside. Whether bees fly in cold weather depends on the genetics, some bees will forage even in the temperatures a bit above 10°C (50°F).

Unfortunately, beehive in snow can be deadly for bees. If sunshine warms the beehive enough that bees think it’s safe to fly, they usually don’t get far and die close to the beehive.

What temperature is deadly for bees?

Once the temperature drops below 12°C (55°F) bees become sluggish. If their body temperature drops below 7°C (45°F) they will die of hypothermia. For that reason, their survival instinct kicks when the temperature drops below 14°C (57°F) and they make clusters.

Honey bee colony forms a cluster to generate heat

In order to keep the colony alive, bees cannot let the temperature inside the hive to drop too much. However, bees don’t keep the whole beehive warm, they only produce heat within the cluster by vibrating their wing muscles.

The diameter of the winter cluster depends on the outside temperature in order to conserve heat. At the temperature of 7°C (45°F) the diameter is around 35 cm, and it is around 25 cm at -25°C (-14°F). The most efficient use of stored resources happens at a temperature of 7°C (45°F).

An outside shell of bee cluster is made of a layer of compressed bees, it is around 7 cm thick. Bees of an outside shell are facing inward while the center is less compressed and bees can move freely to care for brood.

The temperature of the outer cluster in winter is usually around 13°C (57°F) while the center is around 33°C (93°F). If the outside temperature is below 18°C (65°F), you should not interfere with the temperature of the cluster by inspecting a frame outside the beehive.

Usually, the colony cluster is formed below their stored honey and moves closer to the available honey as winter progresses. Naturally, a bigger cluster consumes more honey than a smaller cluster. Temperatures below 7°C (45°F) are deadly for small clusters because it cannot heat up enough.

To preserve heat winter bees have more body fat and larger hypopharyngeal glands. The hypopharyngeal gland of worker bees contributes to the production of royal jelly which is fed to larvae and queens.

Unfortunately, clustering also has a negative side. The warmth of the cluster also keeps hive beetles, trachea mites, and varroa mites alive.

How bees keep the early brood warm?

Since brood rearing happens in late winter, brood is at great risk. Cold temperature would be devastating for bee brood, so honey bees have come up with a way to keep them warm. A heater honey bee sits on top of a honeycomb cell that contains young and generates heat by flexing wing muscles and vibrating her abdomen. Such heating can be even more effective if a heater bee enters an empty cell and generates heat, which heats young on each side of the empty cell. It is believed that one heater honey bee can warm up to 70 adjoining cells. The body temperature of heater bees can reach a whooping 44°C (111°F).

Now that we have covered the basics of what happens in a beehive during winter, we can tackle the question concerning a beehive in snow. Why snow melts at the roof of the hive and is it a bad sign?

Should you be worried about melted snow at the roof of beehive?

Looking at a beehive in snow is so calming and beautiful. It seems so peaceful, as if no one is there. However, as we have learned that is not the case. The bees are very much active inside the hive.

As mentioned before, in winter bees cluster and work to keep the colony warm. You can already guess that some of that heat can also warm up the roof of the beehive and cause the snow to melt.

Melted snow on a hive is a good sign because it means that bees are doing well and manage to keep the colony warm. But, make sure that the bees are not overheating. If the temperature inside the hive gets too hot for the bees, then they will consume more food and be at risk of running out of food. However, don’t use this as an only inspection of your hives. If there is too much snow, the warmth might not be enough to melt it so this method is not reliable. Of course, that doesn’t mean that you don’t have to clean the snow. Bees have to be able to go out when they need to, so beehive in snow can mean trouble. You have to clear the entrance to the beehive. The rest of the snow can be left as it can serve as additional insulation for the beehive. Since bees are very susceptible to cold, we have some common rules of winter beekeeping that will help you keep your honey bee colonies alive.

5 rules of winter beekeeping

  1. Heating beehives in winter is not a good idea. Doing that can trick the bees into thinking the outside temperature is warm enough to fly, which can be deadly.

  1. Give your bees need enough food supplies. If you are not sure whether your colony needs more or less food, it is better to give them more than needed than to let them starve. Have regular check-ups to make sure that your colony has enough food. A simple way of checking whether your bees have enough food is to lift the upper deep a bit and check its weight. In winter days it should be heavier, indicating that there is plenty of food for honey bees. For more details on how to prevent your bees from starving during winter, check here.

  1. Beehive in snow can be a death sentence for your bees. Even in winter bees sometimes go out of beehive because they have to defecate. They have to wait for warmer days when it is safe to fly, and waiting can sometimes take a while. Snow around the beehive can cover the entrances and prevent the bees from going outside. Bees unable to defecate will fill up with toxins and die so make sure to clear the entrance.

  1. Do not open your beehive on cold winter days. Even a small inspection can disturb your bees and put them at higher risk of succumbing to the cold. For better insulation, bees seal all cracks between the hive box so opening the hive breaks the seal. Since winter winds can penetrate the hive, opening the hive puts your bees at risk. If you have to open it, then aim for doing it on warmer days (temperature at least 5°C (40°F)) when the inspection will be less stressful for the bees.

  1. Keep your hive checkups regular to make sure your bees have everything they need for surviving the winter comfortably. For more details on dos and don’ts of winter beehive inspections, check here.

Honey bee colonies are becoming weaker and require more work

Honey bees surviving winter is a natural process that has been happening for millions of years and nature has ways to provide them with heat and food. However, that has changed due to human influence. Everyday use of pesticides around the world decimates bee colonies and make future colonies weaker, which is also shown through colony collapse disorder (CCD).

Since bees today are not as healthy as their ancestors, fewer colonies survive the winter. As a result, beekeepers have to work harder to keep their colonies alive. The work around the beehive in winter can be a stressful time for both a beekeeper and the bees.

We hope this article was helpful in teaching you what happens to honey bees during winter and how to help them welcome spring healthy and strong. Taking care of bees is hard, but arm yourself with knowledge and you have already won half a battle.