Like thousands, Michael E. Nichols, an administrative pastor in Midlothian, Texas, feared the worst for his brother-in-law John when super typhoon Haiyan churned through central Philippines last Friday.
But three days later, a brief one-line message on Google Person Finder restored hope.
"I floated to Vietnam alive and well," John replied, as shown in a screen grab of the Google site posted on Nichols' twitter account.
Many more survivors are being reunited, says Google's Crisis Response center in Sydney, which maintains the site, now in its third year and battle-tested during past crises like the April Boston Marathon bombings, June floods in Uttarakhand, India and the 2011 Japan earthquake and tsunami.
"We're seeing a wide number of entries coming through with people saying 'I've heard from them'," Anthony Baxter, Google's Crisis Response Team Leader told CNBC Asia's "Squawk Box" on Friday.
"It's not just about the people immediately affected - it's about their friends, families. They all want to know what's going on so people can put the updates in the Person Finder and everyone can see, 'Okay, good my auntie's okay'."
While figures showing exact success rates are hard to pin down at this early stage of the crisis, Google says the number of entries in response to Haiyan - currently estimated at around 85,000 - may be on track to surpass the 600,000 seen after the 2011 earthquake and tsunami in Japan, which triggered meltdowns at the Fukushima Daiichi nuclear power plant.
(Read more: Asia rivalries play role in aid to the Philippines)
"From the very limited perspective of this tool, this is as big as Fukushima," Robin Moroney, Google's Communications Manager for Asia told CNBC on Thursday. "We haven't seen it reach this height so quickly."
'Tons of names'
The Person Finder concept is simple.
The free web application, developed by a group of volunteer engineers and first rolled out during the 2010 Haiti earthquake, helps anyone find friends and loved ones following a disaster. Through crowdsourcing, aid agencies, the media and the general public can then update the page with information about those found and the missing.
Re-establishing contact continues to present a huge challenge for those in the Philippines most affected by Haiyan after the super typhoon felled power cables and base stations severing internet and telecommunications access a week ago.
(Read more: Google prepares for the end of the world)
"Mobile networks and the like are mostly down," Baxter said, and as network services are restored "we're getting updates and people are being evacuated."
Meanwhile, emergency services staff and relief workers photographed paper sheets pinned to shelter walls scrawled with the names and personal details of survivors or those seeking family members separated by the disaster. After leaving the stricken areas, they posted what information they had online.
"The moment they got a few bars on their phone or reached an internet café, they'd send it from there," Moroney said, some of them using Google's Picasa photo sharing website. "It filled up with tons of names and we put it on Person Finder."
Also, the country's large community of overseas workers turned to the internet and Google Person Finder in the hope of locating missing friends and family.
Google is looking at improving the application further including ways to merge the information on Person Finder with the data-bases held by the local authorities, first responders and international relief organizations.
"We've actually been working with some of the agencies to build the offline versions so they can take a copy of the Person Finder database go out in the field and update it," Baxter said.
— By CNBC's Sri Jegarajah. Follow him on Twitter: @cnbcSri