>> these slide pads don't have a history of hitting the highway. >> reporter: broken and buried trees mark the spot near jones pass colorado. where a back country skier was buried yesterday. teams are out triggering avalanches like this on purpose before they become threats. this spot hasn't seen a slide this big since eisenhower was president. those intentional slides sometimes triggered with explosives. we watched ski patrollers at copper mountain resort working to make the snow safe. >> how much snow does it take to immobilize you? >> nothing. two or three inches. eporter: a advances this weekend severe weather could spin up in the south, bringing high winds and possible tornadoes. after three dozen twisters last weekend struck four states. here in colorado we're expecting another round of heavy snow tonight. that increases the avalanche risk as this storm pushes east. tom. >> clayton sandell monitoring