Very erratic noise margin since snow started

[#1]

Since the snow began last weekend, my noise margin has been dropping between -7 and -8dB (i.e. from the 6dB starting SNR, it's dropping to -2dB) at various times (mainly in the evenings), with the max rate dropping from 2400kbps to 1400kbps. The SNR will gradually drop for a few minutes until it goes negative and loses the session, and then suddenly the SNR will shoot up to return to normal at which point it remains steady.
My BT Business Hub (2700HGV) hangs onto the connection at its original sync rate (2384kbps for the past 29 days) even when the noise margin goes negative which I'm pleased with because I would go without a connection for a few minutes and keep the 2000kbps IP profile than reconnect at a slow rate and then have to wait several days for the IP profile to go back up.
I'm just wondering if this is to be expected with the current weather, or whether I should raise a fault because something has been damaged? I'm on a bad line (to the point that Plusnet have forced a 6dB to combat the stupid 21CN DLM which was pushing it to 12dB+) but until last weekend the SNR has been fairly steady +/-1-2dB throughout the day.

[#2]

Hi CX23882,
I wouldn't expect a line reporting those kind of rates to be able to hold a connection, and indeed there have been a number of disconnections. The first thing I would advise is that you troubleshoot the dropping connection. We have some helpful advice here.
Jojo

[#3]

Hi,
Thanks for your reply.
I decided to force a resync whilst the noise margin was low, and it seems to be okay now. I've fallen to a 1750 profile, but that's fine. It's still better than I got before joining Plusnet, who have been excellent at getting the best out of my line. I hope that the forced 6dB profile that was applied back in September is permanent. Hopefully once the snow has gone, everything has dried out and everyone has taken down their Christmas lights things will pick up again.