"We're hopeful somebody will be able to remember something or something will strike them," family spokeswoman Shelby Gifford told "Good Morning America."
The family is posting new videos and pictures on Facebook, Twitter and YouTube, hoping to add to the dozens of new leads West Valley City police say they've been getting each day. As of this morning, the Facebook page dedicated to the search for Susan Powell had more than 14,200 members.
CLICK HERE to view the Susan Powell video on YouTube.
Susan Powell has been missing since Dec. 6, the day her husband Joshua Powell packed up the couple's young sons for a middle-of-the-night camping trip in below-freezing temperatures. It was a trip, her famiy has since said, that Susan Powell would have never allowed.
Joshua Powell was named a person of interest by police, who have claimed he hampered the investigation by refusing to answer several questions. He hired noted Salt Lake City criminal defense attorney Scott Williams as attention turned on him.
Investigators said they have uncovered an e-mail from Susan Powell in which she tells friends that her marriage is troubled.
Susan Powell's father, Chuck Cox, told "Good Morning America" today that his son-in law has said little in recent weeks as he brings the boys, ages 4 and 3, to visit.
"We've only had a few words each time as he's dropped the kids off or picked the kids up and he's had nothing to say at all about where Susan might be," Cox said. "He told me a couple weeks ago that he didn't know where she was and there's been no change."
Cox once defended Joshua Powell and said he didn't think he'd be capable of harming his daughter. Now he's hoping his son-in-law will start helping authorities find her.
"It's a difficult situation when we talk," Cox said. "And I try to encourage him to use his attorney and talk to the police."
Cox said that he's confident in the police investigation, but that he doesn't know whether investigators are close to an answer.
"I have no idea where the investigation stands really," he said.
Joshua Powell is also catching flak for taking a 900-mile family vacation to Washington state while his wife is still missing.
"If it were me and my husband were missing I would not have left at all," neighbor Sherry Clauson told ABC News. "My family would have come to me."
Investigators have been out to the area where Joshua Powell reportedly took the boys, but they have not found any evidence to corroborate his story and said he would not show them the exact camping location.
They now say that they have more questions for Joshua Powell about the camping trip, but that he's not talking. He attended a candlelight vigil for his wife before the holidays.
Anyone with information regarding the case can call West Valley City Police at (801) 840-4000.