By By Tim Engstrom, managing editor

What happened on the northern bay of Albert Lea Lake on Saturday nobody knows for sure, but Ken Nelson of 794th Drive was one of the witnesses.

&8220;It sounded like a 747 was going to take off from the lake,&8221; he said.

Nelson went to repair a solar light on his property along the lake shore at about 1 p.m. Saturday. The sound make him look at the sky, thinking it was an airplane. He said the noise lasted about seven seconds.

&8220;I said, &8216;My gosh, I&8217;m going to witness an airplane accident.&8217; That was the sensation I had.&8221;

But there was no airplane. Nelson looked at the ice and saw mud oozing across the ice toward his shore. He saw the hole the geese had made in the ice had opened nearly the length of the bay. He was bewildered.

&8220;What have I been a part of?&8221; he wondered. &8220;Mother Nature just spewed something out.&8221;

His neighbors heard and saw the same thing. Some were on the ice near the shore.

&8220;It was so unusual that they could not believe what they had seen,&8221; Nelson said.

And that wasn&8217;t all. The next unusual turn was the large number of birds &8212; Nelson said thousands &8212; that flocked to the opening in the ice.

Nelson has lived on the shore of Albert Lea Lake for 56 years. He said he has never seen anything happen like this before.

He asked another resident of 794th Drive, Bob Peterson, what he thought. Peterson worked for the city and helped dredge Fountain Lake in the 1960s.

The dredge crew would occasionally hit a pocket of methane gas, he said. That&8217;s what he thinks caused the loud sound and oozing of mud Saturday.

&8220;This must&8217;ve been quite a quantity to boil up like he saw it,&8221; Peterson said.

Vegetation settles into the lake bottom, rotting, breaking down and eventually creating methane, &8220;like in a manure pile,&8221; Peterson said. The methane gets trapped beneath the lake bottom.

&8220;If that indeed is what it was,&8221; Nelson said, &8220;it blew for a long time.&8221;

The Tribune left a telephone message for a Freeborn County Environmental Services technician who had visited the lake but the message went unreturned Monday.

Outreach Coordinator Cathy Rofshus of the Shell Rock River Watershed District said the northern bay takes runoff water from Interstate 90, plus the railroad bridge at the mouth of the bay &8220;kind of acts like a dam.&8221;

As a result, the northern bay builds up extra sediment and vegetation than it normally would, and Rofshus said she thinks is why the suspected methane built up there.

Still, nobody knows for sure it was methane, though it is the most likely explanation.

Freeborn County Commissioner Dave Mullenbach visited Nelson on Sunday. He noticed the ice there was different from lake ice around the area. Area ice &8212; like on Fountain Lake &8212; has been dark and smooth like glass, as if perfect for ice skaters.

The ice on the northern bay of Albert Lea Lake on Sunday was white, buckled and rough, as if it had been heated then cooled again, he said.

&8220;That ice out there was so foggy, broken or rough-looking. I always called it rotten ice,&8221; Mullenbach.