Mussels are frying to death along the shores of Northern California. Jackie Sones, a research coordinator at Bodega Marine Reserve, has worked a Bodega Bay for 15 years and never she seen a sight like this before. “When I was approaching the field site, I could see right away that hundreds of mussels were dead,” Sones told CNN on Monday. As she conducted more surveys, she discovered it was not just hundreds of mussels, but tens of thousands mussels dead along the shore. Sones has seen similar cases before where small patches of mussels die off due to heat, but she has never witnessed something this extensive. When mussels are alive and healthy, their shells remain pressed together. When a mussel dies, those shells open up, exposing the internal tissue or an empty shell. California experienced a record breaking heat wave in June, with temperatures in the north end of the state reaching triple digits. On June 10 and 11, the high in Santa Rosa — 20 miles from Bodega Bay — was 100 degrees. The state issued a Flex Alert that day calling for voluntary electricity conservation. Alerts like these are only issued when outages are plaguing the electricity grid or temperatures are continuously high, according to the California Independent Systems Operator Corporation. Sones said mussels start to struggle physically when temperatures reach 90 degrees. In the case of these mussels, she believes they could have experienced temperatures closer to 100 degrees. Roads are cracking in South Dakota In South Dakota, concrete roads buckled because of high temperatures over the weekend. The high in Vermillion, South Dakota, reached 94 degrees. That number rises even higher when humidity is factored in, bringing it up to a 107-degree heat index. The state’s highway patrol warned drivers of two cases of cracking concrete along Interstate 29. Excessive heat causes the concrete to expand. If the heat is too high, the concrete expands too much, creating the buckle. This buckling typically occurs at weak points in the concrete when the expansions push concrete against the joints and slabs where it is laid, according to CNN meteorologist Brandon Miller. The roads were out of commission for five hours while crews repaired the buckle, according to the highway patrol.