Pop the rear window and run some rope or bungees around the frame and secure it under the rear somewhere.
You should be fine as long as your not driving long distance or on the highway.
2015 Altitude - Billet Silver
SRT Springs, Taillight Bezels, Red Start Button, Pedals & Grille Mesh, Black Lugs,
Mopar 4" Chrome exhaust tips, 1.25" Bora Wheel Spacers, DDM 5500k HID,
Red LED 3157 Bulbs, 15% Tint, Polk DB Center Channel, Mopar All Weather Mats