“An estimated 18,500 southern Arizonans are without natural gas to heat their homes and service may not be restored until next Tuesday. The problem appears to be huge demand for gas nationwide due to the massive storm affecting most of the country. [...] Meanwhile, plans are under review to create huge caverns in salt deposits below the Picacho basin in Pinal County north of Tucson, to store natural gas under pressure to use during times of peak demand.” Quoted from the Arizona Geology Blog.