How Greece's crisis will be felt in the U.S.

The financial crisis in Greece has upended the lives - and livelihoods - of residents of the Mediterranean nation. The shutdown of the banking system has resulted in long lines at ATMs to withdraw a daily maximum of just 60 euros, about $67. Citizens have stockpiled food and fuel, leading to empty shelves at grocery stores and crowded gas stations. Business leaders have warned that shortages of crucial medicines could be next.

It is the worst economic downturn faced by any developed nation since World War II. It strikes at the heart of the single currency that unites the 19-member eurozone and threatens to destabilize a fragile region.

But for Main Street U.S.A., the ripple effects are few and far between. Here are the three big ways the Greek debt crisis - which is likely to intensify in coming days, after Greece rejected a European bailout package Sunday - could affect you.

Your 401(k) could get scary.

Markets around the world plunged after negotiations broke down late last month between Greece and its European creditors. The Standard & Poor's 500-stock index logged its worst day so far this year, falling more than 2 percent. Analysts worried that the turmoil in Greece could signal the end of the six-year bull market in the United States. For those with a 401(k) retirement savings plan, the sell-off was a painful reminder of the volatility on Wall Street during the 2008 global financial crisis.

But it didn't appear to last - at least, not so far. U.S. markets regained much of their ground the next day and ended the short holiday trading week well off their lows. The United States has little direct exposure to the Greek debt crisis, and central banks have done a lot to set up firewalls against a broader panic. Only if the crisis spread badly to other countries such as Portugal and Italy would there be true reason for concern.

Vacations could get cheaper.

The instability in Europe and the massive stimulus program by the region's central bank have sent the euro plunging against the dollar. The currency hit a 12-year low in March - $1.05 - before inching back up. But it began sliding again in mid-June as the crisis in Greece ramped up.

The good news for Americans is that it means every dollar you've saved for that European vacation will go further. Summer is peak tourist season in Greece. Tourism officials have taken great pains to assure vacationers that the home of the Parthenon is open for business, though the U.S. Embassy in Greece released a statement warning visitors to maintain "a high level of security awareness."

Mortgage rates could stay low.

Home buyers have enjoyed low interest rates in the aftermath of the Great Recession, as a weak recovery and Federal Reserve support helped mortgage rates hit record lows Now, after nearly seven years of easy-money policies, the U.S. central bank is considering raising its benchmark interest rate. Many analysts believe it could start hiking the rate as early as September.

But that prediction comes with caveats. Fed officials do not want to cause undue market volatility when it raises rates. They learned that lesson in 2013, the last time they tried to pull back support for the recovery. Then, the mere whiff of a change in the Fed's easy-money stance was enough to send stock markets down the tank while mortgage rates shot up by a full percentage point. If Greece is still in turmoil this fall, and the future of the eurozone is still in question, and markets are exceptionally skittish, the Fed may be reluctant to add more uncertainty.

Granted, that's a lot of ifs. It is a testament to how far this crisis is from Main Street, and a reminder that no one can ever be completely insulated from the crosscurrents of the global economy.