I live in the U.S. and travel to Oklahoma City (known also simply as OKC) often and find the majority of buildings, both private and governmental are of brick and mortar. It's only in the older parts of the residential areas (OKC is a relatively young city, established in 1889 coincidental with the Oklahoma Land Run that began the State) that one finds "stick built" homes and businesses.
The building codes have developed over the years to include numerous items not found in other cities, such as metal rafter tiedown brackets, strapping anchored in cement for modular and trailer homes and, within the last few years a tax rebate is offered if "safe rooms" are constructed. These approximate the old fashioned storm cellars that were once prevalent in the Great Plains States.
Even the brick and mortar homes have weaknesses... especially since most of the roof structures are still wood.
By the way, it's not just Oklahoma City and its suburbs that are at risk... "Tornado Alley" is a well established fact and includes much of Texas, Oklahoma, over half of Kansas and on into Arkansas and Missouri.
This year began as a less than average tornado season due to the late spring (it takes warming of the Earth to produce the effect.) It's just that this particular one was at leas an EF4 or maybe even a 5, with winds in excess of 200mph, whereas most are around a maximum of 120 mph.