With visits to healthcare.gov up dramatically in recent days, more Americans seem to be signing up for health insurance coverage, as the clock ticks down to the end of open enrollment for the Obama health law on March 31.

"As this historic open enrollment period for the Health Insurance Marketplace enters its final days, we’ve seen the momentum gathering across the country," said HHS spokeswoman Julie Bataille, as officials noted the late surge, much like one that was seen late in 2013.

Figures given to reporters on Tuesday indicated many Americans had decided to get moving on their health insurance signups in the exchanges, as 745,000 people visited healthcare.gov on Monday, a 60 percent jump from Sunday; about 800,000 people had signed up midway through March, which was almost as many as signed up in all of February.

"What I can tell you is a lot of people have signed up; a lot more will sign up," said White House spokesman Jay Carney.

But Carney acknowledged that critics won't be satisfied with any enrollment numbers from the White House.

"I am confident that no matter what the number is on April 1st, there will be those who find it insufficient," he told reporters at the White House briefing.

The Obama Administration had originally embraced a projected enrollment figure out 7 million, but adjusted that back to 6 million.

The surge in signups was reminiscent of the rush of applications made in December, before the cutoff date to ensure that you had coverage to start the 2014 calendar year.

This deadline - barring any changes in the implementation of the law - would theoretically bar new insurance signups until open enrollment begins for 2015 on November 15 of this year.

What happens on April 1?

If you don't make the open enrollment deadline, that means you can't sign up for coverage through the exchanges - but are there other options?

Yes - with short-term insurance plans directly from insurance companies and brokers, but those plans would not help you avoid the individual mandate tax penalty.

Exceptions would be made for "life changing events," like losing your job, getting divorced, having a baby and more.

But the basic bottom line is simple: if you fail to meet the March 31 enrollment deadline, you would be subjected to the individual mandate tax penalty for not having health insurance - which is $95 per person or 1% of your income, whichever figure is higher.