Yemen's war has exploded back into the open, and the Houthis' big push toward the coast has already drawn a counterattack that could put them on the back foot — bad news for the group, worse news for oil buyers.

• The Houthis launched a ground offensive on Yemen's west coast, aiming for the city of Taiz, nearby high ground, and the port of Mocha.
• The prize is control over the shipping route where a tenth of world trade passes, giving them leverage over the Red Sea.
• Saudi-backed Yemeni forces hit back from several directions at once, catching the Houthis stretched out and exposed, and now say they want to retake the capital, Sanaa.
• The Houthis answered with their biggest drone and missile barrage on Saudi Arabia in years, setting oil sites on fire and knocking a major refinery out of service.
• Oil prices pushed toward $100 a barrel, and more than 500 fighters have been killed in a week.

Outlook: The Houthis are likely to lose ground on the coast in the coming weeks, but toppling them in their mountain strongholds would take a far bigger and longer war — with oil prices staying jumpy throughout.