The 10-year Treasury yield hit 2.84 percent on Thursday, the highest level in two months. And MacNeil Curry, the head of global technical analysis at Bank of America Merrill Lynch, warns that if yields continue to rise, it will be a very rocky ride for markets.

"If we take out 3 percent, we'll probably get a move up to about the 3.17, 3.30 area," Curry said. "And if we do it with some momentum, then it's going to cause quite a bit of panic."

If yields rise even higher, then more than panic will result.

"Where things would be truly unhinged, you'd need to see a break of, say, 3.6, 4 percent," Curry said on Thursday's "Futures Now." "If that were to transpire, you want to talk about volatility? It's going to be a different ballgame."

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Without predicting that sharp of a move, the technician does see yields going higher as bonds drop.

"We've been in long-term, and we are in a long-term bear trend in Treasurys," Curry said. "All we've done in the past couple months is correct that trend. We've done no damage to that long-term bear trend."

(Read more: 3 technical reasons to be nervous about stocks)

But he stops short of predicting the sort of jump in yields that would wreak havoc.

"We're not there yet," Curry said. "From a technical perspective, we don't quite see that in the cards."

—By CNBC's Alex Rosenberg. Follow him on Twitter: @CNBCAlex.

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