However, there is no evidence of foul play.
Tips on so-called suspicious vehicles were coming in overnight and Wednesday morning, said Lt. Chad Palmiter.
The search area so far has concentrated on the four square miles around the Smith home, which is in Barton Township in Newaygo County northwest of Big Rapids. The search terrain included ravines and corn fields.
Amber, 2, was reported missing late Tuesday when she did not respond to calls from her parents.
Officials said the main concert overnight was the dropping temperatures. When asked about animals in the woods, they said that cold was more of a concern.
(On location reporting by Nicole DiDonato.)