( CNN ) -- A seventh person has been confirmed dead , and the number of presumed dead is now up to three after last week 's flooding in Colorado , authorities reported Thursday . The state Office of Emergency Management added a new confirmed fatality in Boulder County to the list Thursday afternoon , spokeswoman Micki Trost said . And in Larimer County , a 46-year-old man from the town of Drake whose home had been washed away was reclassified as presumed dead , said Nick Christensen , executive officer of the county Sheriff 's Office . Two other people in Larimer County -- both women , ages 60 and 80 -- were already presumed dead after their homes were swept away in the flash floods that ravaged Colorado 's northern Front Range . Another 139 people remain unaccounted for in Larimer County , a figure reduced from nearly 200 on Wednesday , Christensen said . Officials say most of those unaccounted for are expected to be alive and well , but have failed to check in with authorities to let them know . The mountains north of Denver saw more than nine inches of rain on September 12 -- leading to flash floods that turned picturesque canyons into funnels that deluged towns downstream and left hundreds stranded in the mountains above . Nearly 1,200 people had been airlifted out of the mountains by Thursday , and Christensen said nearly 200 more have chosen to stay in their homes . In addition to the deaths , nearly 18,000 homes have been damaged statewide . Gov . John Hickenlooper told reporters that about 200 miles of state highways washed out by the storms will need to be fixed , along with perhaps `` several times more '' miles of local roads . How to help . Those roads are not only in hard-hit Boulder and Larimer counties but in farm communities northeast of Denver , where the runoff from the storms was carried downstream by the South Platte River . And he added , `` It 's clear we 're in a race against the onset of winter . '' `` Critical roads needed to bring in crops that are about to go to harvest are completely broken apart , '' Hickenlooper said . `` This has to be every bit as critical a priority as the roads connecting people with their communities and homes in the canyons . Irrigation , in large measure , has been washed away along the Platte . '' The disaster may end up costing homeowners , businesses and local governments nearly $ 2 billion , according to the insurance consulting firm Eqecat -- and a high percentage of the losses will not be covered by insurance . Tom Larsen , senior vice president of of Eqecat , said that because very many of the homes damaged by the flooding are not in flood plains , the number of people with federal flood coverage is very low . Colorado is also an oil-producing state , and the disaster has raised concerns that hydraulic fracturing , or `` fracking , '' fluids used in oil and gas wells may have been swept up in the floodwaters and washed into the environment . Colorado 's Oil and Gas Association , the industry 's trade association , said no fracking operations were underway when the floods hit -- meaning `` no fracking fluids , no chemicals associated with fracking , nor equipment were on sites at the time of the flooding . '' But state inspectors reported 10 oil spills as of Thursday , including two the Colorado Oil and Gas Conservation Commission called `` notable '' -- a 125-barrel ( 3,900-gallon ) leak from a storage tank south of Milliken , near the South Platte ; and a 323-barrel ( 13,500 gallon ) leak from another storage tank near Firestone , on the St. Vrain River . `` In both cases , it appears the oil left the site in floodwaters , '' the commission reported . It said the spills were `` promptly reported '' by the tanks ' owners , Anadarko Petroleum , and Anadarko said it was working with state and federal officials `` to clean up the releases to the greatest extent possible . '' And the state agency noted that oil is typically a small portion of the contaminants associated with a flood : `` Those include very large volumes ( millions of gallons ) of raw , municipal sewage and other hazards associated with households , agriculture , business and industry . '' What we learned from Vermont 's epic flood . CNN Correspondent Ana Cabrera and CNNMoney 's Chris Isidore and Steve Hargreaves contributed to this report .
NEW : Colorado must race against the coming winter to fix roads , governor says . Seven now confirmed dead , three presumed dead in Colorado floods . Score: 6 State inspectors report 2 `` notable '' oil spills .