Ripping with the grain is much different than cross cutting across it. There are different blades for ripping than for cross cutting. They have fewer teeth per inch as a rule. Also, there are stresses inside the wood that are released as it is cut. Sometimes they will try to open the saw kerf up, but sometimes they will cause the wood to close on the saw blade. I suspect that's what stopped your saw and when you removed the saw the cut closed up? Even chain saws use a special chain when they're going to be used for ripping. But, the right tool to rip a board is a table saw or a band saw. They're designed for ripping. I use the band saw every time as there's less waste. I use it all the time making bows. If you have to use a circular saw, make sure you have a combination blade on it and go slow.
George