By Chad Terhune, Noam Levey and Soumya Karlamangla, Tribune Washington Bureau

LOS ANGELES — Overrun by last-minute demand for Obamacare coverage, California gave many consumers until April 15 to enroll as thousands of people across the nation endured long lines and website troubles.

Despite the problems, the late surge in sign-ups was a substantial boost to President Barack Obama’s signature law, particularly after such a disastrous launch in October.

The final tally from the first year of the law’s insurance expansion won’t be known until later this spring. But as the Affordable Care Act’s inaugural open-enrollment period wound down, an outpouring of interest pushed sign-ups on the new online marketplaces close to the Obama administration’s goal of seven million.

Monday had been the deadline to start signing up for coverage in California. But by Monday afternoon, state officials conceded they couldn’t handle the crowds and offered an opportunity to get coverage over the next two weeks. The state’s website went down periodically during the day while lines at enrollment events swelled into the hundreds.

“We were prepared for a last-minute surge of people coming to our website, but sometimes there’s only so much you can do operationally,” said Peter Lee, executive director of Covered California. “We can’t in good conscience turn people away who simply couldn’t get onto the website on the last day. We weren’t able to build the pipe big enough.”

Under California’s new policy, anyone who tried to enroll by Monday and faced difficulties now has until April 15 to finish an application. The state said no proof is required, so it’s essentially on the honor system.

But those applicants can no longer sign up online on their own. Officials said they must go through Covered California’s call center, an enrollment counselor, insurance agent, county office or health plan enroller.

Supporters of the health care law welcomed the additional time, given the last-minute problems.

“No Californian who tried to enroll should be frozen out of coverage, so this additional consideration is appreciated and necessary,” said Anthony Wright, executive director of Health Access, a consumer advocacy group. “It is both heartwarming to see the lines around the block and troubling because those lines and website glitches may discourage people from even trying.”

Santa Fe Springs resident Stephanie Ybarra, 52, was at the end of an enrollment line in City of Commerce around 6 p.m. Monday behind hundreds of other people when she heard about the reprieve. “I’m glad that they did that for the procrastinators like myself,” she said.

The uninsured woman said she’s eager to get health coverage because she suffers from high blood pressure and migraines.

The national rollout of the Affordable Care Act has been marked by a series of deadline extensions and abrupt policy changes, which have drawn intense criticism from the law’s opponents. Overall, public opinion nationally on the health law has remained deeply split and many Republicans continue to campaign for its repeal.

Americans who are without coverage for more than three months this year may be subject to a penalty on their 2014 taxes of $95 for a single adult or one percent of their adjusted gross income, whichever is larger.

The last-minute surge also overwhelmed the federal HealthCare.gov website, which crashed in the early-morning hours Monday. Technicians repaired it by midday, avoiding a repeat of the meltdown after the site’s Oct. 1 launch.

By 2 p.m. EDT Monday, more than 1.6 million visitors had come to HealthCare.gov; by 4 p.m., the call center had handled more than 840,000 calls.

The heavy traffic on the website triggered an automated message that alerted users that they would have to wait to set up an account or enroll in coverage. The automated queuing system, also deployed in December during a rush of consumers, enables users to enter their email address to be alerted when they can access services.

The federal website is the main portal for consumers in 36 states, including Florida, Illinois and Texas, to select health coverage on the marketplaces created by the Affordable Care Act. Fourteen states are running their own websites, with mixed results.

The surging enrollment prompted new attacks from Republican critics of Obamacare. Sen. John Barrasso of Wyoming said over the weekend that the administration was “cooking the books” on enrollment figures.

But national surveys and reports from insurance companies and state officials indicate that signs-ups for coverage had accelerated rapidly in recent weeks.

Los Angeles teaching assistant Brenda Caceres, 42, said she tried enrolling online at home three times but couldn’t get the Covered California website to work. She gave up and came to an enrollment event Monday seeking coverage for herself and her husband.

“I know a lot of people wait until the last minute,” Caceres said. “And I was one of them.”

In contrast to those in many other states, California’s exchange website had largely avoided major technical problems. But even it was hard hit Monday. To keep the state website functioning Monday, Covered California took the unusual step of logging off some online applicants so that other people could start the sign-up process. Shoppers who were kicked off were told they could return later and complete the application by April 15, officials said.

California’s exchange continued to lead those in all other states with more than 1.2 million enrollees in private health plans by early Monday. Over the weekend, 124,000 people had opened an account on the state website and started shopping for health coverage. An additional 1.5 million people have been deemed eligible for an expansion of Medi-Cal, the state’s Medicaid program.

The state said online traffic Monday at CoveredCa.com was four times as high as the previous record in late December, when applicants rushed in to get Jan. 1 coverage.

That heavy volume prompted considerable frustration for many of the state’s enrollment counselors and certified insurance agents who were trying to help people sign up.

John Anthony Costa, a state-certified insurance agent in Long Beach, said that he needed to enter insurance applications for 25 families Monday, and that he was able to get only four of them into the online system by late Monday afternoon. Meanwhile, wait times at the state’s call centers were exceeding 70 minutes in recent days.

“Every time I try to input the bare minimum, it keeps kicking me off the state website over and over,” Costa said. “This is insane.”

Sarah-Jane George, 36, arrived for an appointment midday Monday at an AltaMed enrollment center in Los Angeles. More than 300 people had shown up there by early afternoon.

An enrollment counselor went over her health plan options and she picked a Bronze plan for about $100 a month. But the state website was running so slow that she couldn’t finish signing up.

Los Angeles college student Mario Estala, 22, showed up at an enrollment event before 7 a.m. Monday and had better luck.

More than 50 people were ahead of him, and it took about three hours before he was seen by an enrollment counselor at the L.A. event sponsored by a labor union. Estala qualified for Medi-Cal and an enrollment worker rang a bell signaling another successful sign-up. Other workers cheered.

“I was relieved” to get coverage, Estala said. “I feel much more safe now.”

Will O’Neill via Flickr