What was the most significant short-term cause underlying the outbreak of the Yom Kippur War in 1973?

There were two primary short-term causes for the outbreak of war in the Middle East in 1973 both of which contributed significantly to the outbreak of the Yom Kippur War. Anwar Sadat had succeeded the nationalist and revered hero, Gamal Nasser, as leader of Egypt and therefore needed to disassociate his own leadership from Nasser's policies to create his own successful legacy and cement political power. As such, Sadat's personal political agenda is perceived as a crucial component to the outbreak of war because he believed that a substantial victory over the dominative Israeli forces would consolidate his leadership of Egypt and simultaneously enable him to finally step out of Nasser's shadow.

The second vital short-term component which led to the outbreak of war in 1973 was Egypt and Syria's need to bring an end to the War of Attrition due to the economic strain it was having on the Egyptian economy. After the 6-Day-War in 1967, Israel's occupation of the Sinai Desert and Suez Canal had led to over 10,000 Egyptian casualties and subsequently, severe economic decline. Israel was 3 times larger than it had been in 1966 and Sadat was suffering huge economic difficulties due to the constant bombardment from Israeli forces and their helicopter raids into Cairo, which were successfully cutting off all electrical power from the city. Consequently, Sadat believed that by bringing an end to the War of Attrition and surprising the occupying Israeli forces by reclaiming the Sinai in an all-out assault, he would be in a position of power that was significant enough to bring Israel and their biggest financial supporter, the USA, to the negotiating table, thus paving the way for US aid to repair the Egyptian economy in 1978 at the Camp David Accords.