Trump: Storms Marco and Laura an 'unprecedented threat' | The World

US President Donald Trump warns that two back-to-back storms have the potential of gathering strength before they make landfall on the Gulf Coast. Yvonne Yong reports. For more from ABC News, click here: https://ab.co/2kxYCZY You can watch more ABC News content on iview: https://ab.co/2OB7Mk1 Subscribe to us on YouTube: http://ab.co/1svxLVE Go deeper on our ABC News In-depth channel: https://ab.co/2lNeBn2 You can also like us on Facebook:   / abcnews.au   Or follow us on Instagram:   / abcnews_au   Or even on Twitter:   / abcnews