smoke problems on reload

I'm in my second year of burning with an RSF Opel III and all has been going well. I burn 24/7 Halloween through mid-March. Natural gas bill for the past month (in Upper Michigan past month has been quite cold) was $30... includes N.G. hot water, furnace, and dryer. So, about $5-$10 more than what we pay in the summer for dryer, hot water, and just to keep the gas on.

However, for the past 3 days or so it has been nearly impossible to load the fireplace becuase when I open the door to do so, I get a billow of smoke rushing out the front rather than up the chimney. I have never had this problem with the RSF. I'm wondering if it is something to do with our current weather pattern or what? It is so bad that I am considering shutting down until the weather changes? Every time I reload, the smoke alarms go off, and I must run the air exchanger full tilt for an hour to clear the smoke smell.

Last year I burned a CSL log once a month simply for peace of mind; but was trying to avoid them this year as they are quite expensive. Didn't clean the chimney til this Fall and ended up with about 4 cups of creosote/ash from about 30' of chimney with two 30 degree elbows... that was quite impressive in my opinion after a previous winter of burning subpar firewood.

So, I burned a CSL last night (becasue they were on sale) and cleaned the ash out this morning - same thing again an hour ago with trying to add wood to the fire. So now I have a rip roaring fire going to heat the chimney up; gonna let it cool through the day; then sweep it tonight for Santa. In a way, hopefully I pull some creosote or something out and this solves the problem - but then again, hopefully I haven't been producing creosote as I have been burning 18 month seasoned maple, oak, and birch this year - and burning it quite well with little fireplace window blackening only around edges.

Any thoughts on the smoke problem?

NOTE: just checked weather data from station about 1/4 mile from my house: barometer = 30.38 in Hg; humidity = 96% (light sugary snow falling); temp = 24.7 F.

Thanks.

All the firewood was cut, split, and stacked 18 months ago... the oak was split to no greater than ~4" splits to speed along drying while maple and birch was split no greater than ~6" splits.

I do open the air intake fully before reloading. Nothing out of the ordinary with bathroom fans or air exchangers or dryers or anything of the like that should affect the chimney draft... I only put the air exhanger to 100% the last couple of times AFTER loading because the smoke in the house was so intense, and thus set off the smoke alarms.

I last (and first time ever) swept the chimney early this fall (end of October I think) and then used the fireplace with no problems so I don't think my cap was inadvertently plugged.

Another thing I've noticed is that my fire itself is not visibly smoking (as it never "visibly" smokes as I burn hot), but when I slowly open the door I get a significant puff of thick choking smoke like I've never had before. I also just got back from having coffee at a friends house and we took note of how his outdoor boiler had smoke that was just hanging there. While we drank coffee and watched out the side window the snow changed from sugary fine stuff to nice thick flakes, and no later than that the color of the smoke coming out of the outdoor boiler seemed to lighten up and also rise much better out of the boiler. He too had noticed upon filling his boiler the past couple days that he was getting much more smoke billowing out the door when loading than what was normal. He also said it was lightly raining early this morning, even though surface temp was just below freezing temp... so the weather definitely has been odd the past couple days. I'm really thinking it's the weather.

I have hot coals remaining now and will let those die down as planned and sweep the chimney late tonight for Santa and see how it goes from there.

Thanks for all suggestions... will report back.