5 things to know for March 18: Mosque attack, plane crashes, Trump tweets, 2020, floods

1. Christchurch attack

It's going to take a while to process Friday's devastating pair of attacks on New Zealand mosques that left at least 50 dead. But changes are already being made -- New Zealand Prime Minister Jacinda Ardern confirmed on Monday evening local time that the government has agreed to reform the country's gun laws. In fact, she said she expects announcement of the specific reforms to come within days. Meanwhile, New Zealand authorities are rushing to confirm the identities of the victims so their families can bury them as soon as possible in accordance with Muslim tradition. As for the gunman, 28-year-old Australian national Brenton Tarrant has been arrested and charged with one count of murder, however, he will most likely face additional charges. New Zealand authorities have also opened an inquiry into the gunman's actions and travels leading up to the attack.

2. Plane crashes

Investigators have confirmed that there are "similarities" between this month's Ethiopian Airlines crash and October's fatal Lion Air crash, but they're not saying anything else for now. Ethiopian Airlines Flight 302 crashed March 10, killing all 157 people on board. It was the second disaster involving a new Boeing 737 Max 8 aircraft in less than six months, and that connection was enough to prompt aviation authorities around the world to ground all Boeing 737 Max 8s until more answers come to light. Air accident experts will continue to examine the black boxes of the two doomed aircrafts to determine what exactly led to the crashes.

3. Trump tweets

The President found a lot to be upset about over the weekend, and he took to Twitter to make sure everyone knew. In a long series of tweets, Trump criticized the late Sen. John McCain, mused about a government inquiry into Saturday Night Live, and demanded that Fox News bring back host Jeanine Pirro. Pirro, whose regular show did not air Saturday, was reportedly suspended by the network after her widely-criticized comments about Congresswoman Ilhan Omar. Though tweetstorms by the President are fairly commonplace now, this one stood out in stark contrast to what pretty much everyone else in the world was talking about: The New Zealand attacks.

4. 2020 election

The Democrats are coming along in their efforts of fielding a whole baseball team of presidential contenders. Kirsten Gillibrand officially entered the race on Sunday, and Joe Biden basically threw his hat in the ring on Saturday when he all but announced his intent to run during a speech in Delaware. Meanwhile, Beto O'Rourke will spend his second week of official campaigning on a multi-state tour of Michigan, Ohio, Pennsylvania, New Hampshire and South Carolina. However, the hot Texas prospect has already landed himself in some hot water: Over the weekend, he apologized for joking that his wife has been raising their three children "sometimes with my help."

5. Nebraska floods

Severe flooding in Nebraska over the weekend broke several state records, and dangerously wet conditions in the area have left millions on edge. About 9 million people in 14 states along the Mississippi and Missouri rivers were under a flood warning as of Sunday evening. The Nebraska Emergency Management Agency (NEMA) says more rivers will break cresting records in the next two days. The floods and cresting are a result of the powerful "bomb cyclone" that slammed the central United States last week, bringing hurricane-like winds and blizzard conditions. Water left behind by the storm ended up in rivers and streams, causing the flooding days after the rain was over.