SIOUX FALLS S.D. (KELO)-- With ice fishing anglers out on KELOLAND's lakes and rivers, we talked to experts about precautions you should take before you hit the ice. DOC official outlines changes in prison system Dakota Angler manager Josh Heitkamp said right now the temperature variations are totally fine for ice formation. "What we're running into is we are tacking on the ice pretty fast so what that causes you'll find the heaves which are kind of like tectonic plates out there, ones going to push up the others going to push down," Heitkamp said. While most of KELOLAND has had colder weather, anglers should still be cautious of the ice. "We still have some softer ice conditions in those areas and that's where this time of year and these kind of conditions that where you start to see some of these accidents happening," Heitkamp said. On Thursday, KELOLAND News reported two people died after a vehicle went through the ice on the Missouri River near Akaska in Walworth County. This past weekend, Day County officials reported two separate vehicles falling through the ice on Bitter Lake. Minnehaha County Emergency Manager Jason Gearman said drastic temperature changes create ice heaves. "Once you get to these colder temperatures, especially the extreme cold temperatures, you see the ice start to thicken considerably and then you start to see the pressure ridges or heaves and those can be very dangerous," Said Gearman. Heitkamp said there are typically telltale signs that the ice might be dangerous. "You will see it just become a ridge formed out on the ice and sometimes those heaves will collapse so you may see a divot or any discoloration to the ice, you will start to see some of that, but for the most part it generally quite visible," Heitkamp said. "You see the heave and on one side of that heave is going to be the weaker ice." Gearman said fishers should be aware of how thick the ice is and if they are planning on venturing out. "4 inches is able to walk on, 4 to 6 you're able to have ATVs and snowmobiles, 12 plus inches you are able to have small vehicles, and 16 inches plus you are able to have some of those larger vehicles." Gearman said that you should never go ice fishing at night unless you have a GPS to guide you to shore or unless you are very experienced, he added that fishers should stick to the trail as well. Gearman added lakes are a lot more stable than rivers because there is no current. Some of these lakes could have currents running into them from smaller rivers. Heitkamp said South Dakota has a great privilege to be able to take their vehicles out on the ice but they should always proceed with caution. "If you are venturing off the beaten path always be checking the ice as you go. There is no such thing as safe ice, all ice is truly unsafe," Heitkamp said. "You should be thoroughly checking the ice as you go, checking all the boxes as you are driving out there, windows down, seatbelts off, and everyone's aware of the situation." Heitkamp said if you are unable to test the ice, a good way to keep track of the conditions of lakes and rivers is to contact local bait shops.