What is it that puts you under the misapprehension that a winter, like we have just had, kills bumbles?
Just not true. They hibernate safely away from the ravages of the cold winter and emerge in the spring when the weather warms sufficiently to arouse them. That is why they hibernate in north facing banks, for instance. So that the soil has to warm from generally warmer air temperatures, rather than from direct sunlight.
Their far bigger danger is that it warms too early, they all come out and are then caught by a prolonged period of very cold/wet weather which may either get them or prevent them establishing a nest.
While they are hibernating they are relatively safe. They have been doing this for millenia in much harsher conditions than we experienced this last winter. All your post does is 'unecessarily alarm' the uninformed to the wrong reasons for the bumble bee decline. Sticking to poor weather in spring and insecticides is much, much nearer the truth.
Had 2 lovely big bumbles sunning themselves on the inside of my bedroom window- gently released- and yes lots in the garden- and saw a red admiral yesterday.
Spring is here, methinks....But still a long haul for bees to really get established with new brood- so tidy the garden - leave bees to sort themselves out. If you must interfere - just sit nearby and watch them working. May satiate your curiosity
Bumble bees have been out and about here for about a fortnight now. I saw my first red admiral yesterday and both swallows and martins have both been spotted on the coast here this week, so perhaps spring has arrived at last.
Its miserable today though started dull and misty now raining hard, although some bees are still out.
I would rather believe the truth, not pander to uninformed newspaper reports and yes, I do live here! I think perhaps you need to read some decent books on bumble bees. I recommend for you 'Bumblebees' by Ted Benton. Very informative and keep you away from using phrases like 'this harsh winter' for a few hours. It was a good deal less harsh than 1963; I can tell you that for sure.