The coronavirus appears to be splitting the mortgage market: More borrowers are refinancing to save money on monthly payments, while potential homebuyers are backing away fast.

Driven entirely by refinancing, total mortgage application volume increased 15.3% last week compared with the previous week, according to the Mortgage Bankers Association's seasonally adjusted index. Volume was 67% higher than one year ago, when interest rates were higher.

After rising for two weeks, mortgage rates plunged to the lowest level in the MBA's survey. The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances ($510,400 or less) decreased to 3.47% from 3.82%, with points decreasing to 0.33 from 0.35 (including the origination fee) for loans with a 20% down payment. That rate was 89 basis points higher one year ago.

As a result, refinance volume surged again. Those applications spiked 26% for the week and were 168% higher than a year ago. The refinance share of mortgage activity increased to 75.9% of total applications from 69.3% the previous week.

"Mortgage rates and applications continue to experience significant volatility from the economic and financial market uncertainty caused by the coronavirus crisis," said Joel Kan, MBA's associate vice president of economic and industry forecasting. "The bleaker economic outlook, along with the first wave of realized job losses reported in last week's unemployment claims numbers, likely caused potential homebuyers to pull back."

Weekly jobless claims soared past 3 million to record high, the Labor Department reported last Thursday.

Mortgage applications to purchase a home fell 11% last week and were 24% lower than a year ago. Real estate agents and homebuilders have reported a sharp drop in buyer interest, and open houses and model homes are shuttering. Some potential buyers are doing virtual tours, but the demand is not even close to normal spring volume.

"Buyer and seller traffic — and ultimately home purchases — will also likely be slowed this spring by the restrictions ordered in several states on in-person activities," Kan said.

The effects of the coronavirus on housing are widespread, but most acute in certain states. Purchase applications are down over 30% in New York, California and Washington state.