Now Playing: What is the Polar Vortex?
Now Playing: Brutally-cold temperatures sweep across parts of the country
Now Playing: Heavy snow hits Midwest amid record-breaking cold
Now Playing: Man rescued from Lake Michigan while trying to rescue dog
Now Playing: Brady, Goff face off before Super Bowl
Now Playing: Dangers of the extreme cold hitting parts of the US
Now Playing: Special counsel probe nearly done, acting AG says
Now Playing: 4 police officers shot during search of Houston home
Now Playing: Polar plunge creates dangerous travel across Midwest
Now Playing: At least 3 killed, 5 seriously injured in pedestrian car crash in Honolulu
Now Playing: 5 Houston officers injured in ambush-style attack; 2 suspects dead
Now Playing: We tried a 12-pound taco you’ll want on the menu at your Super Bowl party
Now Playing: Joshua Tree National Park reopens after government shutdown
Now Playing: 5 Houston officers injured in shooting; 2 suspects dead
Now Playing: Air Force veteran receives a proper burial
Now Playing: St. Louis police officer charged with involuntary manslaughter
Now Playing: Former Starbucks CEO considering 2020 presidential run?
Now Playing: Health emergency in Pacific Northwest involving measles outbreak
Now Playing: 2 men facing charges in road rage incident
Now Playing: Government shutdown cost $11 billion to economy
Read More