Replying to building a backyard jump????

OK i just got like 3 in of snow and we are getting like 4 more tonight. Today i went out and built a pretty nice kicker with a flat landing from shoveling all the snow in my yard into a pile... however when i tried to hit it i didn't have nearly enough speed even with a starting ramp. I poled it and tried to get as much speed as possible but still didn't even get off the ground. My yard has a very very gradual decline so i thought if i built a starting ramp i should be fine but i am still having problems getting speed. Any advice?