Tuesday: Last day to enroll in health coverage

Sign up -- or pay serious fines for not having health insurance.

The deadline to enroll is December 15 if you want to be covered starting January 1, and officials tell us this Tuesday was the busiest day for online enrollment and sign-up offices across the country.

"My brother just moved to the United States a year ago," said Olga Mikhailova, who was first in line at a Connect for Health Colorado office. "He's looking for health insurance."

Millions of Americans are enrolling in record numbers to comply with the Affordable Care Act, now in its third year of expansion. The federal phone systems were tied up Monday because of the number of callers. Connect for Colorado said it had to expand its online capacity to allow for more users to enroll.

"We're seeing more volume, so we have more customers coming in than we have in previous years," said Luke Clarke, Director of Communications for Connect for Health Colorado. "We are at about twice the number of enrollments we were on this date last year."

One reason for the rush is higher fines for people who are not insured. The fines are up almost 50 percent, according to a study done by Kaiser Family Foundation. For the average family, it could cost almost $1,000.

While Tuesday is the enrollment deadline for January 1 coverage, open enrollment doesn't officially close until January 31.

The White House says Detroit, Milwaukee and Philadelphia are doing the best in terms of sign ups, while cities like Denver, Dallas and Las Vegas are lagging.