Explain why the Tsar abdicated in February 1917 / 12

In March 1917, the army garrison at Petrograd joined striking workers in demanding socialist reforms, and Czar Nicholas II was forced to abdicate. Nicholas and his family were first held at the Czarskoye Selo palace, then in the Yekaterinburg palace near Tobolsk.

Reasons for the February Revolution, 1917

Tsar Nicholas II was a poor leader. Economic problems grew, made worse by Russia's disastrous involvement in World War One. Social unrest led to the February Revolution and his abdication.